; ae + § e 
ath 3 y £ 
20 Human Foot-Prints in Solid Limestone: 
species of Pentremite here represented, (Fig. 3,)* is also a very 
common fossil. Three other species: have been ob- Fig. 3.. 
served in this rock: the Pentremites ovalis of Gold., ; 
the Pentremites florealis of Say, and the Behweni: 
tes globosa of Say.t The above corallines and Cri- 
noideans are peculiar to these beds. Hence I have 
been accustomed to designate this group of rocks here 
in the west, as the Pentremital limestone, and its Up- pontromites 
per bed as the Archimedes limestone. I am not aware pyriformis. 
that these organic remains have been discovered in the Atlantic 
_ states. is pst the: Archimedes limestone that our coal meas- 
ures rest. 
ing from beneath ‘the great Illinois coal-field,t 
| toné’ beds ¢ cireumscribe it nearly in its whole extent; 
a visible, ‘one of other of the above characteristic 
L uniformly be f 
] “These. fossils afford a valuable 
IS y v ikdaietiiiddg the 
bearing rocks} since no workable seam of coal has ever been 
found, either in in Indiana, | Illinois, , Ken } y, or Tennessee, be- 
neath the rocks in which they | oceur, Without a oubt some one 
of these fossils can. be discovered in the vicinity of St. Louis at 
low water. I shall ‘not: fail to. avail: myself of the first favorable 
opportunity of Fadi Hits: matter. ‘<¢ 
* The Pentre 
t A Pentremite, but of a species” very different from any ‘o these, occurs ina 
stratum of rock at the falls of the Ohio; the probable equivalent of the We 
formation of Murchison; the same rock describe in the a of western geolo- 
gists, and popularly known here as the cliff rock 
t Delineated and de scribed in my Bayon of a 
Treasury of the United States, i Sir the autumn of the year 18 
take this. opportunity of correcting an error with iba to this same coal- 
felt, » whieh has crept into a notice (in this Journal, Vol. xt, 1841) of a geological 
, f Which, as geologist had pais to its np weet 
in in tha winter ote. ‘bo that notice (at p.1 I ur bitu 
portion of that territory are included in the coal formation. 
=e acs Sree eam a a 
> > SA kee Ese eae ce 
i ss yi . srk Tt Nie Dace Ei oe 
le lal 
2 aaa 
Re Oe Sen Se Sa eee ea ae ne ee N 
te Ger 
Sih an ie a ey 
pee tan Vets 
cbt 
