162 
PALAEONTOLOGY OF NEW YORK. 
the present time. Two of the most abundant, and, so far as known, widely 
distributed species, the T. gyracanthus and T. attenuatus, occur in very dissimilar 
deposits—one of them being in a limestone, while the other occurs in an 
arenaceous or semi-argillaceous formation. These, in their respective horizons, 
can be traced for the distance of more than three hundred miles in a northeast 
and southwest direction, while they have a very limited extension to the 
westward. Since, as a rule, these fossils occur in limestone or in semi- 
calcareous deposits, it seems a little remarkable that neither T. attenuatus or 
T. spiculus should be found in the western extension of their respective 
formations, in which direction the sediments become more calcareous. In the 
single example of T. scalar if or mis, we find a greatly increased number of 
individuals in a westerly direction, as far as Ohio, but this is strictly along 
the trend of the limestone formation. 
The following tabular arrangement of species described under the generic 
name of Tentaculites will show their distribution in the American Palaeozoic 
rocks: 
SPECIES. 
Lower 
SILU¬ 
RIAN. 
Upper 
Silurian. 
Oriskany sandstone. 
Devonian. 
! Trenton and 
Hudson River. 
Niagara and 
Clinton. 
Lower Ileld- 
erberg. 
m 
1 
©'S 
£ 
Hamilton. 
Chemung. 
T. arenosus ......... 
* 
. . 
T. attenuatus ........ 
* 
T. bellulus ......... 
* 
T. distans ........ 
* 
. . 
T. elongafcus ........ 
. . 
* 
1 
. . 
T. fissurella ........ 
* 
T. lloyti ......... 
. . 
* 
T. gyracanthus . . . . ... 
* 
T.incurvus .. 
. . 
* 
T. minutus ........ 
* 
T. Niagarensis .. 
* 
T. Oswegoensis ....... 
* 
T. Ilichmondensis .. 
* 
T. seal arifor mis ....... 
* 
T. sicula ......... 
* 
. . 
T. spiculus ........ 
* 
T. Sterlingensis .. 
* 
. . 
T. subtilis ........ 
. . 
. . 
* 
T. tenuistriatus .. 
* 
*• 
