852 University Geological Survey of Kansas. 
pected to exist, and those which occur only intermittently 
through the section. In the first case the species are those 
which are usually abundant and hardy and the first to migrate 
into a region where favorable conditions are newly established 
and the last ones forced out of it by the introduction of untow- 
ard conditions. In the second place there are fossils like 
Streblotrypa prisca Gabb and Horn, Allorisma costatum 
and A. terminale Hall, which occur only at rare inter- 
vals. Such species cannot be said to occur “throughout” a 
‘series of rocks without implying a serious error. There are, in 
such cases, large groups of strata in which they may not be 
found. The study of their occurrence in such cases may lead 
to the discovery of the wedging out of strata, or of unsuspected 
overlap, or even unconformity, which would otherwise go un- 
noticed. The occurrence of Rhynchotrema dentata in the In- 
diana Ordivician is a case in point.? They are of special 
significance, when thoroughly worked out, in indicating the 
nature and extent of communication of former water bodies 
and the more accurate geologic history of the region. 
So far as the present paper is concerned these species oc- 
curring at intervals are of no especial interest, as no deductions 
may be drawn from them, but when similar studies have been 
completed in the surrounding regions they may have consid- 
erable significance. 
There are some 36 species found in the Cherokee shales or 
in the Fort Scott limestone and in the uppermost horizons of 
‘the Kansas Coal Measures. They are distributed as follows: 
Anthozoa, 1; Vermes, 1; Bryozoa, 5; Brachiopoda, 13; Pelecy- 
poda, 9; Gastropoda, 4; Cephalopoda, 2; Trilobita, 1. Out of 
about 400 species some 36 species range nearly through the 
series and 25 completely so. That is, about a sixteenth of the 
species are of the widest ranged types. There are somewhere 
in the neighborhood of 50 new species to be added, and several 
known species of which we have no definite horizon. Thus, 
taking the whole fauna, the species of greatest range probably 
constitute five or six per cent. of the whole fauna. However, 
this fails to express the whole truth in the matter, because 
many species, such as Spirifer cameratus Mort., Spiriferina 
kentuckiensis (Shum.), Squamularia perplexa (McChes.), 
Aviculopecten carboniferous (Stev.), Lima retifera Shum., 
-and many others with large but definitely restricted range, de- 
279. Cumings, 32d Ann. Rep. Ind. Dept. Geol. Nat. Res., 1908. In press. 
