GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 591 



horizon as her zone H. The age of the Santo Domingan corals is dis- 

 cussed on page 218 of this volume. The Foraminifera, among which 

 are no orbitoids, and the Bryozoa, both groups abundantly repre- 

 sented, give essentially the same result as the corals. Messrs. Canu 

 and Bassler consider the Bryozoa from zones H-I as of unquestion- 

 ably Burdigalian age. 



This same horizon, that of the Bowdcn, has been recognized at num- 

 erous places in Cuba, as has been stated in discussing the fossil coral 

 faunas of Cuba (p. 218). It has been identified at Baracoa and Matan- 

 zas, and perhaps at Havana and Santiago. The lower (Alum Bluff) 

 Miocene of the southeastern United States has been discussed at 

 some length on pages 572-574. Marine deposits of this age occur in 

 Florida, Georgia, and southern Alabama; in Mississippi they are 

 represented by the nonmarine, plant-bearing Hatticsburg clay. 



A fauna of very nearly the same, if not identical, age occurs on 

 the Isthmus of Tehauntepec. It has been particularly considered by 

 Bose and Toula. 1 Bose says, regarding the specimens collected by 

 him: "Eine ganze Eciho von Arten stent solchen nahc, die nur aus 

 dem OligocJin der Antillcn bckannt worden sind." Although 

 precise correlation of this material is not now practicable, it seems 

 that a lower Miocene horizon is represented. 



Dr. C. W. Hayes collected on the Pacific coast of Nicaragua, 75 

 miles northwest of Brito Harbor, station 6409, worn specimens of a 

 species of bryozoan that Dr. R. S. Bassler says is apparently Cupularia 

 canariensis Busk, which ranges from a horizon in the Alum Bluff 

 formation to Recent. The matrix is a calcareous, sandy, consoli- 

 dated marl, and was included by Hayes in his Brito formation. 

 The age of these specimens is not older than, and it probably is, old 

 Miocene. The Brito formation, therefore, includes deposits ranging 

 stratigraphically from upper Eocene to lower Miocene, but the beds at 

 the type locality are of upper Eocene age (see previous pp. 193-197). 



It was stated on page 5S6 that H. Douville considered that part of 

 the Gatun formation exposed around Mount Hope as Helvetian 

 Miocene, and that I provisionally accept his determination. It is 

 probable that some of the Miocene deposits of northern Colombia are 

 also of this age. Information on Venezuela and between there and 

 Martinique is lacking. 



For Martinique we have the following statement from Cossmann: 2 



D'apres un premier apercu qui ne porte que sur une partie des Siphonostomes, il 

 prait a peu pres certain qu'un grand nombre de Gastropodes se trouvent a la fois dans 



i Bose, E., Zur jungtiaren Fauna von Tehuantepec. I. Stratigraphie, Beschreibung und Vergleicli mit 

 americhanisehen Tertiarfaunen, K. k. geolog. lteichsanst. (Wien) Jahrb., vol. 60, pp. 215-255, pis. 12, 13, 

 1910. 



Toula, F., Zur jungtertiaren Fauna von Tehuantepec. II. Vergleichung hauptsachlich mit curopfiiscben 

 und lebenden Arten, Idem, vol. 60, pp. 255-276, 1910. 



* Cossmann, M., Etude comparative de fossiles mioceniques recuellis h la Martinique et h. l'isthme do 

 Panama, Journ. conchyliologie, vol. 61, pp. 1-64, pis. 1-5, 1913. 



37149— 19— Bull. 103 4 



