302 The American Geologist. Ma.A, is9s 
Stcinmann for description. He writes that on a hurried ex- 
amination he finds that they do not seem to bear any great 
resemblance to the fauna Pilsbry treats of, but that he is not 
prepared at present to give any opinion as to the age of the 
strata. 
Tn the most recent Tertiary strata in Terra del Fuego 
veins of lignitic coal and vegetable remains are found in many 
places, and one might assume that we had a fresh-water forma- 
tion here, corresponding to the Santa Cruz beds in Patagonia. 
In a specimen of a clay, however, from the Cullen river, de- 
posited immediately beneath and in contact with glacial gravel, 
the clay being in other respects free from fossils, Cleve has dis- 
covered remains of a tolerably rich marine flora of Diato- 
macese : hence, it seems most probable that this clay is an 
analogue of the Cape Fairweather beds. 
The Tehuelche, or boulder formation mentioned above, is 
not only the most peculiar of the deposits in Patagonia, but 
it is also the one about the mode of whose origin the greatest 
diversity of opinion has prevailed. The deposit is as much as 
sixty metres thick, and plainly consists of stratified shingle 
and gravel, sometimes mixed with sand. As the result of in- 
vestigations made by Darwin, Doering, Sieniradzki, Am- 
eghino and others, it has been supposed that this deposit ex- 
tended uniformly over the whole of Patagonia — high plateaus 
and lowlands alike — up to the Colorado river. The majority 
of the investigators who have considered the question have 
held the deposit to be marine ; some, and Steinmann among 
them, have connected it with the glacial period of these 
regions, without, however, as a rule, expressing any opinion 
as to the mode of its formation. Hatcher embraces the former 
hypothesis by reason of the above-mentioned fact that the 
shingle formation passes into the Cape Fairweather beds be- 
low. As now formations similar to these beds would not at 
present seem to have been come upon anywhere but at a 
hight of from lOO to 150 metres above the present sea-level, 
and in the immediate vicinity of the shore, the observation 
made does not afford reasons enough to assume, for so late 
a period, such an immense depression of the land, of necessity 
nearly 1,000 m. at least. If this were so it would be strange 
