THREE CRUISES OF THE “ BLAKE.” 
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one hundred fathoms they equal in bulk the grains of sand, and in 
greater depths they become the chief constituents of the sea bottom, 
thus gradually passing into and leading us to the true calcareous globi- 
gerina ooze, and finally disappearing into the red clay formation, in the 
deeper parts of the Atlantic basin. 
* In the mud of the ‘ Block Island soundings,’ and of the ‘ mudholes " 
off New York, we find very little besides a few Guttuline. 
“The same general distribution prevails all the way to Cape Florida, 
with few exceptions. Interruptions are rare in this great sandy plain 
of the continental shelf. We find only one or two small rocky patches 
in the neighborhood of the entrance to New York Bay.” 
A triangular area of clayey bottom, of considerable extent, 
within the hundred-fathom line, extends within the usual limits 
of the siliceous sands south of Block Island. The northern 
and southern extensions of this clay deposit, as it gradually 
fades, or is covered by globigerina ooze, can be traced many 
miles along the slope of the continental shelf. 
Professor Bailey noticed in the soundings off Montauk Point, 
in fifty-one fathoms, an extraordinary development of forami- 
nifera, rivalling in abundance, as he says, the vast accumula- 
tions of analogous forms constituting the marls under the city 
of Charleston, S. C. In the more southerly soundings of sim- 
ilar depths, a greater number of globigerinz are found, as well 
as other genera known to occur in large numbers round the 
shores of Florida and the West India Islands. Professor Bailey 
also calls attention to the fact that these Mexican and Caribbean 
types are not represented in the chalk, but are very common in 
the tertiary deposits; their absence from deep-sea soundings 
seems to afford additional evidence of the difference in depth 
at which cretaceous and tertiary beds have been deposited. He 
further suggests that the immense development of globigerine 
and other pelagic foraminifera, forming a perfect milky way 
along the course of the Gulf Stream, may be due to the high 
temperature of its surface waters; and that the deposits under 
Charleston may have been produced under the similar influence 
of an ancient Gulf Stream. According to Bailey, the sound- 
ings around the Atlantic shores and in the course of the Gulf 
Stream present no analogy to the vast accumulations of infusoria 
which occur in the miocene marls of Virginia and Maryland. 
