THE HAMILTON ASSOCIATION. 1 23 



Such a Structure is obviously that of a rhizopod rather than that of 

 a sponge. Further, the arrangement of the laminse and pillars is 

 very nearly allied to the Parkeria and Loftusia, as described by 

 Carpenter and Brady." 



I am here quoting Dr. Dawson's remarks. He further says : — 

 "The supposed oscula on which has been based a reference of these 

 forms to sponges are certainly not constant. Although these forms 

 have a strong resemblance to Eozoon, the main structural difference 

 is that while Eozoon has a delicately tabulated proper wall of num- 

 muline tpye, that of stromatopora has coarse perforations and pores." 

 In the great Niagara limestone, as seen at Niagara Falls, the masses 

 of stromatopora occur precisely as Eozoon occurs in the Lauren- 

 tian lyiiestones, and are mineralized with quartz and dolomite, and 

 often converted into crystallized masses void of any structure. The 

 first general impression was, that these forms belonged to the family 

 of the sponges, the idea being that the lateral pores and openings 

 were the inhaling, and that the perpe»dicular tubes and pores and 

 vermiforn star-like openings were the exhaling oscula. These 

 are distinctly seen in those classed as Coenostromae, and in Caunopora 

 Walkerii, also in Caunostroma Restigouchense and others ; still there 

 are other forms which show nothing that can be considered as an 

 osculum. It would seem that they cannot be classed with the for- 

 aminifera, as they show no pure nummulitic wall. Yet I think that 

 Dr. Dawson and Carpenter lean to this view. There also seems 

 a difficulty in placing them with the sponges. Why not place them 

 with the Hydrocorallinae, or Milleporae ? These forms build or 

 deposit on other forms layer by layer, as does the stromatopora, 

 and the tubules in the laminse of the Millepora Alcicones have 

 much resemblance to the former. There are structural differences, 

 but we find the most extraordinary differences in the many forms of 

 stromatopora. Although the forms of the Milleporae of the pres- 

 ent day may be much modified from the ancient type, it is nc 

 greater than what we find in other forms. If they should be found 

 to belong to the Hydrocorallinse, they are existing at the present day 

 in great masses on the coral reefs and attached to shells, seaweed or 

 other forms, as did the stromotopora of old. I have* found the 

 stromotopora enter by enveloping a favorite, also entirely sur- 

 rounding a group of Diphyphyllum and other corals, also surround- 



