THE HAMILTON ASSOCIATION. 83 
“one 
are found remains of Coral building forms and Molluses, which cor- 
respond to those of the warm and shallow seas of the present day ; 
and in other regions, as in the confines of this city and at varicus 
points in the Maritime Provinces, are entombed the remains of 
animals corresponding to the Sevtudarians (Graptolites), Pteropods, 
Glass Sponges and other forms of the open ocean.” 
I infer from the foregoing extract that Professor Matthews en- 
tertains a view, held by many Palzontologists even now, that the 
Graptolites (Ancient Sertularians) were confined to shale beds and 
indicated deep sea bottom. He may not be aware that this class 
of organic remains has numerous representatives in the Niagara 
limestones of Ontario associated with Pteropods (Conularias, four 
or five species), Glass Sponges (many undescribed as yet), Bryozoans, 
Brachiopods, Fucoids and Corals. Certainly the two latter were 
not likely to live in water of any very considerable depth, and if we 
assume that the Archaeans of this continent acted as a barrier and 
protected the Mediterranean Sea from cold Arctic currents, it seems 
difficult to explain where such could find an entrance at all, save, as 
the Atlantic does now through the gut of Gibraltar, in an undertow. 
It must be admitted that several Graptolites occur in the Niagara 
shales, but they are found in the limestones below as well as in the 
blue building beds above this material. Indeed, several of the 
layers bear a striking resemblance to some modern Coral Reefs, 
especially the ones called by quarrymen ‘‘The Sand Beds.” Why 
so called I am unable to say ; it may be because they are not unlike 
certain of the Medina freestones in color. It is an exceedingly 
difficult manner to determine the depth of the Paleozoic Seas from 
the Brachiopods embedded in the rocks. These constitute a con- 
siderable majority of the shells found fossilized in these rocks, and 
the species still existing appear to feel as much at home in deep as 
in shallow warm water. 
Again, taking the Trilobites for instance, we all know how veiy 
numerous the head and tail shields of the Crustacean are in our local 
limestones. They may have drifted shoreward from deep water 
after decay. Single valves of Zingulella occur in great abundance, 
but we rarely find the complete shell, and only occasionally can we 
ascertain if it has been fossilized in its burrow. Fucoid sea plants 
afford us more reliable indications regarding the laws of distribution, 
