ON SOME FOSSIL AND KECENT LITHOTHAMNIEAE OF 

 THE PANAMA CANAL ZONE. 



By Marshall A. Howe, 



Of The New York Botanical Garden. 



INTRODUCTION. 



The following report is based chiefly upon a number of specimens 

 of fossil calcareous algae, of the group known to geologists as " Nulli- 

 pores," from Oligocene and Pleistocene strata in the Panama Canal 

 Zone, collected in 1911 by D. F. MacDonald and T. W. Vaughan, of 

 the United States Geological Survey. 



In this material the Pleistocene period is represented by a single 

 collection (MacDonald, 6039), consisting of numerous excellent free 

 specimens, " from flats near Mount Hope, five feet above tide level." 

 These Pleistocene specimens appear to the writer to belong to a 

 species found by him a year or two earlier to be living in the Colon 

 region, only a few kilometers distant. This species, so far as the 

 writer can determine, has been hitherto undescribed ; in framing its 

 diagnosis, as published below, the fossil as well as the recent mate- 

 rial has been considered, but a recent specimen, being more complete 

 and satisfactory for detailed study, has been named as the technical 

 type of the species. 



So far as the present writer has been able to discover, the fossil 

 coralline algae of America, in their taxonomic aspects at least, offer 

 a practically untouched field for research. It is, of course, possible 

 that geological and paleontological papers in which calcareous algae 

 have been described have escaped the attention of phycologists, but 

 inquiry among American geologists and paleontologists and a search 

 of accessible literature have thus far revealed to the writer but a 

 single x hitherto described species of fossil Lithothamnieae from the 

 Western Hemisphere, namely, Lithothamnium curasavicum K. Mar- 

 tin, from the Island of Curacao, a species to which further allusion is 

 made below in the discussion of Archaeolithothamnium episporum. 



1 Stromatopora compacta Billings (Palaeozoic Fossils, vol. 1, p. 55, 1S62) from the 

 Island of Montreal, etc., has sometimes been considered by geologists to be of corallina- 

 ceous affinities (the species has been referred to Solenopora by Nicholson and Etheridge, 

 Geol. Mag., vol. 3, p. 529, 1885), but, if we may judge from published figures, the organ- 

 ism seems to the writer hardly a coralline alga, if indeed it is an alga at all. 



