Ci'UptoxiKin find otlirv Aitc'u'iit Fossi/fi. 



•200 



('xliil)it ciiiiiils only in j)lii('es. KIscwIhto tlicv niuy have 

 ])eiluii»s lieon destroytMl hy (k'ciiy iiml pressurtf. Miittlicw 

 re^iu«ls these; forms as fossils; and if so, they are 

 undoulitedly allied to Cryptozoon, if not properly belon^'- 

 in«' to the <'eniis. Thev an; in any case the oldest known 

 forms referal)le to this type, in other heds of the same 

 aj^'e fragments of Kozoon showing the; canal systems have 

 been found, and also neeilles siijijxjsed to he sjtieides of 

 sponges, and carhonaeeous films and tlhres which may be 

 of \'ei:etabl(; oi'iuin. 



III. (Jknkkal Hkmaisks on Cryi'Tozoon and Ahcilko/.oox. 



If we endeavour in imagination to restore these curious 

 organisms, the task is a very difficult one. They no doubt 

 grew on the sea l»ott(jm, and must have had great jiowers 

 of assimilation and increase in bulk. Still, it must be 

 borne in mind that they were largely made up of inorganic 

 particles collected from the mud and tine sand in process 

 of deposition. The amount of actual organic matter in the 

 hard parts even of large specimens is not very great, and 

 the soft living material, if they were animal, must have 

 been confined to the canals and to the exterior surfaces. 



As the only marine animals known to accumulate 

 foreign matter in this manner are the Protozcja of the 

 iihizopod type, one naturally turns to them for analogies, 

 and j)erha])S species of the genus Loftusia most nearly 

 resend>le them in general arrangement. J5ut this tyi)e is, 

 I believe, not known lower than the Lower Carboniferous ; 

 /.. Cohiinhiana, A. M. Dawson, found with the genus 

 Kusulina in rocks of that age in IJritish Colundjia, heing 

 the oldest known species.' I am not aware that any of 

 the Stromato[)orce, projjerly so called, as nearly resemble 

 Cryptozoon, unless my genus Megastroma from the Car- 

 boniferous of Nova Scotia is referable to that group. 



- Journal London Geol. Suivey, Vol. ;)'), \\. »W, ct sim|1'. 



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