Reviews — Dr. Bornemann — Cambrian Fossils of Sardinia. 227 



The Trilobites of the lower zones are stated by the author to pre- 

 sent a genera] resemblance to Paradoxides and Olenus, though for 

 the most part they are specifically and even generically distinct from 

 any forms yet described ; in a somewhat higher zone examples of 

 Illcenus are associated with survivors of the older forms. 



The description of the Trilobites is. however, reserved for another 

 part: the fossils treated in the present one are ranged under the heads 

 of Plantee, Spongite and ArchaBOcyatbinas. The forms described as 

 plants are, at the best, doubtful. Thus the author, accepting the 

 views of Lebesconte, de Saporta, and Delgado, places Cruziana as a 

 genus of Algse. In Sardinia, as elsewhere, there is not a trace of 

 organic structure in these fossils, and there is nothing to controvert 

 the striking arguments of Nathorst (whose name is not even men- 

 tioned by the author) that they ai'e most probably tracks or im- 

 pressions. 



A new genus, PhytocaJyx, is proposed for conical or hemispherical 

 bodies, which weather out of a sandstone rock in considerable abun- 

 dance. No structure whatever is preserved. The}'^ are regarded 

 as AlgEe analogous to Fucoids or Siphoneas ; but, judging from the 

 description and figui'es, it seems to be equally as probable that they 

 may be inorganic concretionary bodies or infilled casts of hollows 

 made by burrowing organisms. 



Another new genus, Epiphyton, is stated to consist of fan -shaped 

 groups of cells which are regarded as formed by a lime-secreting 

 Alga allied to the Sij)hone8e. 



Another form, growing in small rounded masses, like Nullipores, 

 and consisting of an agglomeration of minute curved tubes, is 

 extremely abundant, forming in places whole beds of rock. The 

 author regards it as a new genus of calcareous Alga, and finds a re- 

 semblance in the form, arrangement, and dimensions of this Cambrian 

 marine fossil to a species of existing Alga which grows on the 

 surface of calcareous rocks in Switzerland. Some of these land- 

 Algae also secrete lime, and form hard stony crusts, and the author 

 thinks there is reasonable ground for placing the fossil in the same 

 group with the recent form ! 



We may here point out the fact, that this genus, which the author 

 names Siplionema, is by no means new, as he supj)oses, since it was 

 clearly described, and the tj^oical form figured, by Nicholson and 

 Etheridge, juu., nine years since, in their Monograph of the Silurian 

 Fossils of Girvan, under the name of Girvanella (I.e. p. 23, pi. ix. 

 fig. 2i). As the writer has had the opportunity of seeing both the 

 specimen described by Dr. Bornemann, as well as that which has 

 received the name of Girvanella, he can confidently state that they 

 are generically identical. 



Singularly enough, the same fossil occurs at a similar geological 

 horizon in the United States, and it has lately been described by 

 Prof. H. M. Seeley as a genus of free calcareous sponges under 

 the name of Strephochetiis (American Journal of Science, vol. xxx. 

 1885, p. 355). Thus for this same fossil we have the following 

 references : — 



