CORRELATION OF STRATA. 
CXxVli 
Table showing number of species restricted to each of the Lower Silurian groups in the 
upper Mississippi region, nwmber of same occurring in one or more of the four other 
regions, and the formations in which they are found. 
Ale =] 
s} 2] 3 : 3} 2) 5 ‘ 
Saleslalela) |= Balgsle|ela| |¥ 
Of El ax Qi. SslEE] a meee, 
Esse \elalela Besagialala|s 
SET eal| ecules || S Bass, 8/2/2/3|8 
me jo |a|mA@ la |e |e a ja/ala|e|s 
F Stones River group...| 4) 0 Stones River group...| 49} 18] 15} 2) 1 
3 Black River group... | 6) 3 3 § | Black River group....| 29) 9 1) 6) 2 
= | Trenton group........ Sines 3 a Trenton group........ 60} 20 1) 19 
= Wihicareroupseccrs-<s- 0. 2) 2 2 5 Wiitike) EAU scosodacade 4) 2 2 
© | Richmond group...... 6] 4 4] © | Richmond group.....- 8} 2 2 
a Stones River group....| 5} 0 3 Stones River group....| 22} 9} 6} 2) 1 
4 Black River group....| 11) 0 3 Black River group....| 6] 1 1 
& Trenton group........ 10| 4 4 2 Trenton group........ 9} 3 5 
E S| Utica group........... 0} 0 e | Utica group........... (0) ) 
i) 
8 | Richmond group...... 6 © | Richmond group...... 1] 0 
Stones River group. 24) 11] 11 _ | Stones River group....| 15) 7 
2 | Black River group....| 56] 6 2) 1) 3 3 Black River group....| 32) 1 1 
S Trenton group.......- 45| 15 15 3 Trenton group........ 13} 3 Hl ie 1 
& | Utica TOU Pstere sisi ele’ ill) a Utica group...... emaren|t vOlbn 1 
Richmond group....-. 10| 6 6| | Richmond group...... 4) 2 2 
Se ee ee ee ae eS SSE ee eee eee 
s Stones Rivergroup....| 10) 6] 5 1 Stones River group...| 10) 6) 5) J 
3 Black River group....| 11] 5 4| 1] 1 € | Black River group....| 0} 0 
3 Trenton group........ 24) 10) 10 6 Trenton group........ 13) 7 6 1 
= | Utica group........... 7| 3 i) 2 Ep mUlbicaleroupieeeeeasce: (a) 
| Richmond group...... 15] 9 1 8 Richmond group...... 3] 0 
Ss 
= | Stones River group....| 25] 3) 3 3 Stones River group...|164| 60} 52) 5) 3 
2 | Black River group....| 38) 6 6 = | Black River group....|189] 31) 4/ 21) 6) 1) 1 
g Trenton group........ 44) 1] 11 = Trenton group........ 227) 76 2) 72 2 
= Gs 
ae eWibi Gay oTOMpya-eeeecree Bj) 3 3 i (Witicayenoulpsemereers-- 22) 11 1} 10 
= | Richmond group..... 14| 10 10 Richmond group .... | 67] 33 1 32 
3 group 
Found elsewhere in 
Found elsewhere in 
