Correspondence. 195 
One of the finds here was a single specimen of Scala 
, making the first specimen of this species known from 
these deposits. The specimen was excellently preserved. A single 
specimen of Scala groenlandica Perry, was found here many years 
ago and was noted in the writer's' previous list of the Sankaty Head 
fossils. 
Another species of interest was Cerithiopsis greenii C. B. Adams, 
of which but very few specimens have been found at this locality. 
This specimen was also excellently preserved, showing the proto- 
conch complete. 
Among the smaller shells collected were several species of 
Odostomia. Of these the two species previously reported from 
Sankaty — Odostomia impressa Say and O. trifida Gould, — were the 
most common, the former being represented by at least three times 
as many specimens as the latter. Besides these two species there 
were found O. fusca C B. Adams, O. bisuturalis Say, and O. semi- 
nuda C. B. Adams. These three species have not previously been 
reported from Sankaty. 
Among other things of interest was the finding of Area pon- 
derosa Say in situ, both valves being together and in the position 
of life. This species was previously knov/n from this locality by a 
single valve found by the writer among the material collected by 
Dr. Scudder. Other pelecypods were found in the lower layer with 
both valves attached and the shell in the natural position. This 
tends to show that, the shells of this layer at least are in situ and 
not secondarily deposited. 
The crab claws collected included three species. They were 
identified by Miss M. J. Rathbun as Callinectes sapidus Rathbun, 
Eupanopeus herbstii Milne Edwards and Neopanope texana sayi 
Smith. The last was much more common than either of the other 
species. 
In the collection at Nantucket were found two other species 
of very considerable interest as they were unknown from this 
locality at the time of publication of the former list (Am. Geol. vol. 
xxxiv, Sept., 1904). These include a specimen of Sipho stimpsoni 
Morch, with an excellently preserved protoconch and a large speci- 
men of Chrysodomus decemcostatus Say. This latter is a fairly 
complete specimen, part of the body whorl being broken away, but 
the spire in good shape. 
Joseph A. Cushman. 
Boston Society of Natural History, September, 1905. 
Field Geology in Ohio State University. Each spring term an 
elective course in Field Geology is offered by professor Prosser for 
advanced undergraduate and graduate students. The purpose of 
the course is to acquaint the student with the formations as they 
are seen in the field and to train him in the methods of investiga- 
tion employed by the working geologist. The course consists of 
field excursions, laboratory work and study of library references. 
