280 The American Geologist. April, i»»4 
models, maps, sections and photograpjjs in teaching, was il- 
lustrated only by products, — a list of thesis subjects and ref- 
erences, and some geological maps of small local areas, by 
students. The region about Cambridge is divided into areas 
of a mile square and each year a student is assigned to an 
area ; the various geologic features are indicated by as many 
colors as are necessary. The accuracy of the work is tested 
by comparison with a manuscript map prepared by the in- 
structor and by special excursions to the area. The variety 
of features found in this region appears in the note given be- 
low describing tile photographs exhibited. Library research 
is carried on by the students following the thesis list and ref- 
erences, and the results of such investigation are given orally 
to the class or written in thesis form. 
The next step in geological training is a field course, the 
advanced summer school. A map including southern New 
England and a large part of New York state showed the dis- 
tricts visited by the school: and the details of the Catskill 
and Meriden regions were shown upon maps of a larger scale. 
Specimens collected at the localities studied and systematically 
arranged showed the lithological and paleontological evidence 
by which the structural geology is determined. As now ar- 
ranged, this summer work begins at Utica, N. Y.. with the 
horizontal Palaeozoic formations. Abundant fossils aid in 
identifying horizons, and by a series of sections the sequence 
of formations is determined. A considerable part of the same 
series of strata is identified near Catskill, N. Y., but is divided 
into two unconformable series, folded and faulted. The folds 
are of the Appalachian type, on a small scale, and display 
well the relation of surface form to structure. About Meri- 
den the Triassic sandstones of the Connecticut valley are 
studied. The evidences for the intrusive and extrusive origin 
of the trap sheets are carefully observed. By a series of ex- 
cursions the faulted structure of the region is demonstrated, 
and by means of maps and sections estimates of the amount 
of dislocation are obtained. Student note books represented 
products of the course. 
The final course in general geology is one of research under 
the direction of the instructors of the department. Products 
only were exhibited, consisting of geological maps and sec- 
