66 tROCEEDINQS OF THE ACADEMY OP [1886. 



some resemblance to Mr. Nicholson's Dictyostroma, is found at 

 the same locality at Louisville, but the descriptions given by 

 Nicholson, and his figures, sufficiently prove that it was not this 

 form which served him as a type for Dictyostroma. The rather 

 closely approximated laminte are inflected upwards to form stout 

 conical pillars with a funnel-shaped excavation at their base, 

 as in Clathrodictyon and in Stylodictyon of Nicholson. The 

 pillars of the superimposed laminae correspond, and the 

 apices of the lower pillars become invaginated into the basal 

 cavities of those above, whereby a sort of pseudo-columns are 

 formed which vertically intersect the entire thickness of the 

 masses, growing in flat expansions and covered with an epithecal 

 crust on the underside. A number of other interesting forms of 

 Stromatopora occur in the Niagara group, but as my present 

 intention is only a review of Messrs. Nicholson and Murie's 

 work, I abstain from their description on this occasion. 



