1877. ] Geology and Paleontology. 49 
hard work. It must be completed in time, by a long series of new re- 
searches, and nobody is better able to continue them on the same plan 
than Dr. Hayden, who has directed them until now with such thought- 
ful zeal and clearness of plan. The magnitude of the results already 
obtained warrants the hope of future discoveries. —Count G. DE 
SAPORTA, of Aix, France. 
Tue GEOLOGY or ITHACA, New York, AND THE Vicinity. — The 
Cayuga Lake basin of Western New York extends in a general north 
and south direction, attaining a length of over forty miles. The land 
inclosing it on the north is comparatively low, and the lake is broad and 
shallow. Southward the land increases in elevation, the lake becomes 
deeper, and the head of the basin is inclosed by a high hilly region. 
Along the shores of the lake for its entire extent the various rocky 
strata from the Salina group to the Chemung are admirably exposed, 
Ithaca occupies the low alluvial plain at the head of the lake, about four 
hundred feet below the general level of the surrounding country. Many 
of the streams entering the valley at this point flow through deep gorges 
rendering the underlying Chemung rock easily accessible. From Fall 
Creek, which flows into the lake basin just north of the village, south- 
ward to the Pennsylvania line there is a continuous stretch of Chemung 
strata. Excepting for building-stone and flags, the economic value of 
this group is not great, as it is made up of shales and thin beds of sand- 
stone. The characteristic fossils found at Ithaca are Spirifera mesacos- 
talis, S. mesastrialis, and Orthis impressa. In addition to these there 
are a number of species of lamellibranchs, gasteropods, cephalopods, — 
some of which are quite large, — and brachiopods other than those men- 
tioned. The best, and in fact the only, exposure of the Portage group, 
which underlies the Chemung, is immediately below the Ithaca Fallin the 
Fall Creek Gorge. This has afforded well-preserved fossils, some of 
which are quite rare. Spirifera levis, characteristic of the strata, occurs 
in great numbers, and so well preserved that the spires are frequently 
visible where the shell has been removed. But the exposures along the 
lake shore offer a richer field to the collector. By reference to a geological 
map of New York the various rocks of the Silurian and Devonian ages 
will be seen to stretch in long bands from east to west, that is, the beds 
all dip to the south and are imposed one upon the other in their regular 
order. As the Cayuga Lake basin cuts them transversely, it forms the 
basis of an excellent section of the western part of the State. The 
Hamilton formations are here well deyeloped and are exposed along the 
lake shore for a distance of twenty-five or thirty miles. North of Ithaca 
the black, thinly laminated Genesee Shale is met, and, forming cliffs 
along the shore and precipitous walls to the small streams entering the 
lake, it continues exposed for two or three miles, thinning out and over- — 
lapping the Hamilton rocks proper. This~shale affords very few fossils, 
though some well-preserved plant remains have been found. Separat- 
p ae 4 ii 
