Palcontological Speculations. — Grafocap. .87 
pression of the Ordovician time. To be sure the fossil remains 
from these limestones are mainly Cambrian, but apart from the 
fact that these limestones have not been thoroughly explored 
their relations to the shore fauna, (properly to be considered 
Cambrian) as an invasion of the deep sea would have led to the 
deposit of Cambrian genera and species within them, while 
their own more characteristic residents, beyond the continental 
limit, might not have at once followed them inland. The pter- 
opodous species of these limestones are pelagic and might have 
naturally moved shoreward with the deepening of the Cam- 
brian shore-line. Where indeed their fossil contents are typ- 
ically Cambrian the limestone seems generally arenaceous or 
of a shore origin, and in these cases it is not clearly shown 
that the fossils are as numerous in individuals or species as 
those of the slates and sandstones, nor whether they represent 
fossilized individuals in situ, or current-transported specimens. 
In many cases the fossils of the limestone suggest the presence 
of an articulated brachiopodous fauna, or one of greater size 
and skeletal mass, as contrasted with the inarticulates of the 
Cambrian shallow waters. So in Ford's Troy section Orthis, 
and Lepcrditia fPlcctaiuhonites) appear, and in the limestones 
of the Nevada sections the predominance of Agnostus"^^ and Pty~ 
choparia indicates an Ordovician affinity, while other genera of 
triolbites (Protypus, Diccllocephahis, Olenoides ) being 
glabellate( ?) and therefore of relatively more skeletal mass, 
are later forms than the Olenelliis or Paradoxides and point to 
an outlying bathymetric fauna. 
If this proposition receives further corroboration we are pre- 
sented with a biological picture of this sort. 
Along the Pre-Cambrian coast-waters a process of devel- 
opment or creation, ensued from such protistic bodies as may 
have secured proper elaboration, which resulted in a synthetic 
type of annelids. From these in divergent directions came the 
trilobites and the brachiopods, the latter deviating into the 
heavier shelled genera and families in deeper water, and rep- 
resented in shallower depths by the ecardines, the former mul- 
tiplying in swimming forms along the coast with the more 
♦Agnostus extends into the second fauna and also has a very wide geo- 
(iTi-a'^hi al dis'rbuiion in thf iii-imoi d al i-dcks In fact Harande states the 
single connexion between tlie primordial and the following faunae is through 
Agnostus. 
