Mineralogy and Geology. 117 
drawn on stone by Mr. Salter of London, the well known English paleon- 
tologist, is alone a sufficient guaranty for their accuracy; but we can ; 
rom a personal knowledge of many of these forms, our own testimony 
that they are faithfully represented. 
By reference to our former notice of this memoir, alluded to above, as 
originally published without figures, it wi seen we were then im- 
pressed with the remarkable coincidence of the characters of several 
forms described, with those of old and well known species. But as no 
author has now, however, added good figures of many of these fossils, 
described by others, and here offer some critical notes embodying our 
conclusions. 
in his N, Am. Geol., p. 51, as Terebratula Mormonii. Figure 2, Tere- 
bratula geniculosa McC. represents a well known species described man 
years back in this Journal, by Dr. Morton, from Ohio, as 7. bovidens, and 
more recently by Prof. Hall under the name 7, millepunctata, in vol. iil, 
n, after 
careful examination of authentic specimens from the Illinois localities, 
consider it the common Spirifer Urei Fleming. If future comparisons, 
however, should show it to be distinct, Prof. McChesney 
not stand, since D y 
noconvexus, in 1858; see Missouri Geol. Report, page 202. Figure 4, 
quently referred by them to the genus Streptorhynchus, to which it prop- 
erly belon Fig. 6, Orthis Lasallensis McC. is almost certainly only a 
variety of the last. Upon such trivial differences, species may be multi- 
plied indefinitely in a genus like this. Fig 7, Productus asper McC., fig. 8, 
P. Wilberantis M d fig. 9, P. symmetricus McC., ee —— ly 
suspect, only varieties of one species, apparently very closely allied to the 
European >. scabriculus ; if distinet from that shell, however, Norwood 
y 
