131 
feet their igneous nature was not conclusively shown. The 
other two could not be found.” 
* Being in the vicinity of Ludlowville recently I undertook to 
rediscover the dikes mentioned by Vanuxem and was unusually 
successful in locating the same. This was probably due to the 
fact that the summer has been the most rainy in many years and 
not only were the streams badly swollen, but the rock forming 
the sides of the gorges had been freshly broken off and washed 
down thus furnishing an excellent opportunity for study. 
The best results were obtained in the gorge of Townley’s 
Creek, a branch of Salmon River, on land owned by Mr. Howell, 
between the series of cascades locally known as The Indian Falls. 
Although this ravine could not be identified as Vanuxem’s 
“third ravine east of Ludlowville,”’ the appearance of the falls an- 
swered so closely to his discription that it left little doubt in my 
mind that it was the original locality. If this be the case, subse- 
quent erosion has exposed more of the dikes for this careful obser- 
ver speaks of but four dikes in all, while seven distinct dikes are 
now visible in this gorge, as follows: 
Drxe I. About 75 yards east of the first falls, that flowing 
over the Tully limestone, this dike may be found, crossing the bed 
of the creek at nearly right angles. It occurs in one of the joint 
planes of the Genesee slate, as do all of the others of this locality. 
It strikes N. 10 degrees E., magnetic. 
It is one-half inch in thickness in the shales on the north 
bank of the creek, becoming thicker as it crosses the bed of the 
creek to the southward. ‘Twelve feet from the north bank of the 
stream (as far south as it was accessible) it was 6% inches 
wide and apparently increasing in width toward the opposite side 
of the stream. This was easily ascertained as the dike forms a 
noticeable depression in the bed of the stream, which at the deep- 
est point measured was 16 inches below the adjoining shale rock. 
On the south side of the stream this depression was 15 inches in 
width, which is of course somewhat thicker than the actual 
breadth of the dike. Its width could not be accurately obtained 
because of the depth of water in the stream at this point and the 
detritus filling the depression. In the cliff a short distance to the 
