MARKINGS, FOOTPRINTS AND FUCOIDS 325 



markable inferences of Matthew already referred to, respecting 

 cuttlefishes in the Cambrian period, constitute a case in point. 

 Footprints of Batrachians in the Carboniferous rocks were known 

 before their bones. The strange hand-like tracks in the Trias 

 were known before we knew the Labyrinthodon that produced 

 them. We are still ignorant of the animals whose tracks in the 

 old Potsdam sandstones we name Protichnites. 



References : — On Rusichnites (a form of Bilobite), Canadian Naturalist, 

 1864. On Footprints of Limulus compared with Protichnites, etc. 

 Ibid, On Footprints and Impressions of Aquatic Animals and Imita- 

 tive Markings, Amer. Journal of Science^ 1 873' On Burrows and 

 Tracks of Invertebrate Animals, Quarterly Journal of Geological 

 Society, 1890. On Footprints of Carboniferous Batrachians, "Acadian 

 Geology," "Air-breathers of the Coal Period," etc. 



