124 JOURNAL AND PROCEEDINGS 



ing an Orthoceras. I have lately found one form of stromotopora 

 entirely enclosing another. 



As this subject is still under consideration by many specialists, 

 I shall not give you more than the few remarks already made, but 

 will show you specimens of Eozoon, Loftusia, Milleporge and many 

 forms of stromatoporse from the Clinton and Niagara, of our own lo- 

 cality, and other forms from the Guelph and Devonian. You 

 will be able to judge how they vary in structure ; also, how obscure 

 and poorly preserved some of them are. Although you will see 

 many beautiful specimens, there are still many others belonging to 

 the Niagara that I have not as yet obtained. 



It would be as well, before we discuss these specimens, to get a 

 general idea of their structure. This is what Sir J. W. Dawson says 

 of a well-preserved specimen from the corniferous limestone of Ohio : 

 "In these the concentric laminse and pillars of the fossil in the con- 

 dition of opaque calcite, apparently retaining its minute structure, 

 and not affected by crystallization, and the interspaces or chambers 

 are occupied by transparent calcite, permitting all the structure to be 

 very well seen in transparent slices." 



In these specimens about three interspaces and two laminae oc- 

 cur in the space of a millimetre; and though neither the lamina 

 nor the interspaces are uniform in thickness, the latter are about twice 

 the width of the former. In some places the laminae rise into coni- 

 cal or rounded eminences with corresponding depressions ; in others 

 they are nearly flat and concentric, this difference being apparently 

 accidental.' The laminae are connected with each other by pillars, 

 which are either round or somewhat flattened. The texture of the 

 laminae is not spicular, but perfectly continuous and finely granular, 

 as if made up of minute fragments of calcite. When the mass is 

 broken parallel to the laminae, the pillars appear as minute tuber- 

 cles (but a true exterior surface is smooth.) The lamina are pierced 

 with numerous round pores about one-tenth of a millimetre in diam- 

 eter. Some of these pass through hollow pillars across one inter- 

 space into the next. The laminae themselves are here and there 

 pierced with horizontal tubes, which thicken the laminae where they 

 pass ; they appear to traverse the laminae obliquely from one space 

 into another, or from the hollow pillars laterally. They may be 

 called canals. In addition to the ordinary lamina, some of the 

 chambers or interspaces are sub-divided by very thin secondary lam 



