feet; descent, 2.93 feet; and least depth, 10 inches. A dam closing the right chute of Maple Island would probably be the means of washing out a better channel and improving the depth.

Rapids, 110.5 miles below Olean.-Above this point a bar from the left throws the water across to the right, giving a passageway only 100 feet wide. There is here a sharp rapid, the water in 130 feet falling 2.09 feet, with a depth of 1.4 feet. The only trouble comes from the swiftness of the current.

Hemlock Creek Island, 111.9 miles below Olean.-The length of the island proper is 900 feet, and its width is about 200 feet. There is a small island of the same name well in shore, opposite the mouth of Hemlock Creek (which enters from the left). On the left bank, and above the creek, an enterprising citizen has erected an extensive hotel called the President House. It is noticeable chiefly because there are no other buildings near it. The channel passes down the right chute of Hemlock Creek Island. For some distance it is quite narrow, being driven close to the main shore by the head of the island. Length of ripple, 1,140 feet; descent, 3.4 feet; depth, 1 foot. The bottom is composed of loose rocks, some of which could be removed to advantage. A few of these rocks project more than a foot above the surface of low-water.

McCrary's Bar, 112.8 miles below Olean.-This bar, now covered at a 4-foot stage, was formerly an island. It is 1,500 feet long and 250 feet wide. The channel passes on either side, there being no material difference in the depth. There is a gentle ripple entering the right chute with a depth of 1.8 feet. Six hundred feet below McCrary's Bar, another bar, in mid-river, 900 feet long, and covered at a 14-foot stage, confines the channel to the left. At its foot a bowlder reef extends entirely across the river. The depth on this was only 4 inches. The river falls at this place 1.48 feet in a distance of 70, which is certainly a remarkable jump.

Plans for improvement are deferred for the present. Thirteen hundred feet below, opposite the mouth of Henry Run (which enters from the right), there is a gentle ripple with a depth of 1.1 feet; it gives no trouble.

Pit-Hole Islands, 115.3 miles below Olean.-These are two small islands. The channel passing to the right of the upper one is wide and shallow, and full of loose bowlders. Pit-Hole Creek, a considerable tributary, enters from the right, opposite the foot of the first island. Its mouth is 100 feet wide. Two railroad bridges (one railroad extending up the valley of Pit-Hole Creek) cross it.

From the mouth of the creek the best channel (still in the right-band chute) passes close over to the second island, hugging it to its foot, leaving a number of small, dry bars to the right, and others extending some distance below.

This is an exceedingly swift place, the river falling 4.65 feet in 1,300, or at the rate of about 18 feet per mile. The depth found was not quite 1 foot. Scarcely a vestige remains of Pit Hole, which was once a center of the oil excitement. At one time its post-office was the second in importance in Pennsylvania.

Walnut Islands, 116.8 miles below Olean.-The first island is 1,700 feet long and 500 feet wide. A head bar extends above it a distance of 1,300 feet. The channel is to the right. In entering, passing between the bar and the right bank, the channel is only 100 feet wide and 10 inches deep. The ripple in this place descends 2.61 feet in a distance of 1,360.

The second island is 1,000 feet long, and it commences immediately below the first. The channel is on the right, and it has several small detached bars on each side. The ripple at the lower end it 910 feet in length, with a descent of 1.92 feet and a depth of 1 foot. A wide-spread rippleoccurs in the river about one-half mile farther down. Its length is 1,390 feet, and its descent is 2.90 feet, but as the least depth observed was 2 feet, no improvement seems necessary. Four more ripples occur at intervals in the river to Alcorn's Bar, a farther distance of about 4 miles, but they give a navigable depth greater than 1 foot. In this reach a number of small islands and bars occur, but the channel holds to the right of them all.

Alcorn's Bar, 122.4 miles below Olean.—This is a long bar in mid-river, just below a little island called Horse Creek Island. The bar is 3,000 feet long and is 250 feet wide, and is covered at a stage of 34 feet. The channel is on the right of the bar, where there is a ripple 2,100 feet long, with a descent of 1.37 feet, and a least depth of 1.2 feet. At the extreme lower end of the bar another ripple is found 500 feet long, with a descent of 1.99 feet, and a depth of 1.9 feet. There is no special difficulty at either of these ripples. The Imperial Oil Refining Company, one of the Standard Oil Company's works, is located on the right bank. It is the first oil-refining establishment met with below Olean, and is said to be the most extensive in the United States. It certainly pollutes the river with enough refuse to justify the encomiums that are passed on its capacity. Allegheny Valley Railroad Bridge, 124.4 miles below Olean.-This bridge crosses the river diagonally. It is a covered wooden structure on the Howe truss principle, with three spans, each 150 feet long, elevated in the clear 29 feet above low-water. The channel is under either the left or the central span. Oil City, on the right bank, begins at this bridge, and South Oil City is found on the left bank. These two places together have a population of about 8,000. The highest recorded flood in the Allegheny at this

point occurred in March, 1865. Our levels up to the mark show that the river rose on that occasion 174 feet above the low-water mark. This is only 1 foot higher than the river is reported to have risen at Olean in 1873. The channel between the railroad bridge and the Oil City bridge is nearest to the left bank, leaving a low bar, once an island, on the right.

Oil City Bridge, 124.8 miles below Olean.—This bridge crosses the lower end of the bar referred to, its right shore abutment being about 200 feet above the mouth of Oil Creek, a large tributary of the Allegheny (on this stream are the towns of Petroleum Centre and Titusville). The length of the bridge is 1,100 feet, divided into 6 spans, the longest of which measures 200 feet. The height in the clear above low-water is 29 feet. About 900 feet below, the river is crossed by a suspension bridge divided in three spans, the longest measuring 500 feet. The total length of the bridge is 700 feet, and it is elevated in the clear 41 feet above low-water. A rocky ripple occurs between the railroad and the suspension bridges, measuring 1,100 feet in length, with a total descent of 3.25 feet, and a least depth of 1.3 feet. Two-thirds of a mile below the suspension bridge a large bar, which is covered at a 4-foot stage, makes off from the left shore, and throws the channel to the right. It is not a tronblesome place. Length of ripple, 275 feet; descent, 1.16 feet; depth, 2 feet.

Holliday's Bar, 126.9 miles below Olean.-Here an extensive bar 2,200 feet long, covered at a 4-foot stage, again confines the river to the right shore. The ripple is 900 feet long, with a descent of 3.56 feet, and a depth of 1.4 feet. No particular difficulty at this point.

Schaeffer's Bar, 128.3 miles below Olean.-At this point a large bar on the right, covered at a 4-foot stage, confines the river to a width of 150 feet close to the left bank. Through this chute for 1,900 feet the current is strong, the descent being 3.25 feet, with a least depth of 1 foot. At its lower end there are a number of rocks in the channel. The river is shoal for mile below this ripple, with a least depth of 18 inches, and a considerable current.

Two-Mile Run Bar, 130 miles below Olean.-At this point a flat bar, 1,100 feet long and 200 feet wide, covered at a 14-foot stage, confines the channel to the left. The depth on the ripple is 7 inches; length, 450 feet; descent, 2 feet. Much water is lost to the right of this bar, which might be utilized to advantage by closing that side with a wing-dam 400 feet long.

McDowell's Islands, 131.4 miles below Olean.-These two once made a continuous island, but at some time prior to 1853 they were cut through near the lower end. Their united length is 3,000 feet, but with head bar and connecting bar they measure 4,800 feet. The channel is down the left, which is shoal throughout the entire chute. In 4,800 feet the river descends 4.20 feet. The least depth in the channel is 1 foot, but it is generally about 2 feet deep.

French Creek, Franklin, 132 miles below Olean.-French Creek enters from the right immediately below the foot of McDowell's lower island. The survey was closed at this point October 21, 1879. French Creek is the largest tributary of the Allegheny. It heads in New York, and drains about 1,050 square miles. Conneaut Lake, on one of its branches, was the source from which a portion of the water supply for the Pennsylvania Erie Canal was drawn. It is a noteworthy fact that a dam raising this lake only a few feet enabled its waters to flow into a canal which discharged into Lake Erie. Frankiln, immediately below the mouth of French Creek, has a population of 6,500.

1

Tabulated statement of the ripples, falls, &c., on the Allegheny River, between Olean, N. Y., and Franklin, Pa.

water.

Depth in

low.

Tabulated statement of the ripples, falls, &c., on the Allegheny River, &c.—Continued.

Feet. 1,239.25

Feet.

Feet.

Feet.

51.78

52.27

52.57

78

Schoonover Falls

52.72

79 Harrison's Ripple.

81

Kinzua Island (head)

1, 228.85

800

3.42

0.9

82 Kinzua Island (foot)

54.86

85

Little Bars Ripple

0.86

09

86

Kinzua Creek Ripple No. 1

1,214 61

375

1.38

0.8

56.68

88

Kinzua Creek Ripple No. 3

56.83

89

Bent's Run (upper)

57.82

90 Bent's Run (lower)

58.04

91

Catchall Bar..

59.47

59.88

95

Shipman's Island

60. 19

96

Hook's Island (head).

400

99

100

101

98 Shipman's Island No. 2 (head)

Shipman's Island No. 2 (foot)

Lower Shipman's Bar....

.....do

1.98

0.8

104

Mile Island...

550

1.85

0.7

0.9

107

Just above Warren

1.96

2.9

68.48

109

Reese's Eddy (head of).

110

Mead's Island (head)..

0.9

70.56

1, 162. 69

175

0.61

1.0

72.27

72.61

0.85

1.4

73.03

116 Grass Flat Island (foot).

0.53

117

Ripple.

1. S

73.67

118

Cluster of bars

0.8

119

Fish Dam Ripple

120

Brokenstraw Island (head).

121......do

1, 147. 91

525

2.42

0.8

76.55

77.67

78.23

126

Clark's Island

79.46

1, 132. 82

800

1.98

1.0

128

Thompson's Island (foot)

129 130

Farley's Island (head).

Farley's Island (foot)

2,100

3.10

1.2

131

Smith's Bar (upper).

83.48

133

132 Smith's Bar (lower).

Millstone Bar.

1, 117.83 83.73 1, 116. 35

84.09 1, 115. 47

600

1.40

20

84.98

136

Goose Neck Ripple.

1.87

1.0

1.8

89.88

1,097.87

375

1.73

0.6

90.17

1.0

1.7

91.49

1.0

91.99

1.0

93.93

145

White Oak Chute.

1.58

03

10

Tabulated statement of the ripples, falls, &c., on the Allegheny River, &c.—Continued.

97.06

Feet. 1,071. 69

Feet.

Feet.

Feet.

155

Dale's Island

The 190 ripples average 617 feet in length and 1.6 feet in descent. Their aggregate descent is 304.77 feet, which, deducted from the total descent of the river between Olean and Franklin, leaves 141.49 feet, or an average descent of 1.07 feet per mile for the residue of the river. In length the shoals are 17 per cent. of the entire distance. From the mouth of French Creek to Pittsburgh, 123 miles, there are seventy-five ripples, the total descent of the river in that distance being 261.7 feet.

It is proper for me to add that for much of the substance of the detailed description of the river above Franklin I am indebted to Mr. John B. Dougherty, assistant engineer, who conducted the survey in the field. Being called to the East on other work, he was unable to make any regular report himself, but left his notes and field books with me. I will note here that the adopted elevation of Olean was taken from the late geological report of Pennsylvania, one volume of which is devoted to tables of elevations of various railroad points within the State and on its borders. Since this table was prepared I have received the elevations adopted by the canal surveys of New York, from which it appears that our elevation at Olean is 14 feet lower than theirs.

Respectfully submitted,

Col. Wм. E. MERRILL,

Major, Corps of Engineers, U. S. A.

S. Ex. 89- -3

THOMAS P. ROBERTS,
Assistant Engineer.

water.

Depth in

low