SANTO DOMINGAN PALEONTOLOGICAL EXPLORATIONS 225 
France, and pronounced them of Miocene age.' They raised the 
question, of late years also set forth by Dall, whether more than one 
formation was represented. They called attention to the resem- 
blance of certain of the fossils to the recent deep-sea and Pacific 
forms. Indeed, the brief article of Moore shows a highly philo- 
sophic interpretation of the data. Later, in 1872, Dr. Guppy 
of Trinidad, on a trip to London, reopened the Heneken collection, 
made a number of excellent illustrations, and described some of the 
specimens which further study had showed to be new.? 
Gabb agreed with these pioneers in assigning a Miocene age to 
the fossils from the Yaqui Valley, but emphatically denied the 
possibility that more than one formation was represented, coin- 
ciding in this with Heneken. Gabb regarded the entire valley as 
made up of fossiliferous beds of late Miocene time. The belief 
that this constituted a stratigraphic unit led him to disregard 
entirely localities and zones in collecting, and his otherwise fine 
collections are very seriously marred by having been labeled solely: 
“Miocene, Santo Domingo.”’ 
Our 1916 expedition was undertaken with the express object of 
determining the exact stratigraphic sequence. The party con- 
sisted of the writer, Mr. Karl Paterson Schmidt, and Mr. Axel 
Olsson. Despite the dangers of the revolution led by Desiderio 
Arias, we succeeded in collecting over four hundred species of 
molluscs, many corals, bryozoa, foraminifera, echinoderms, and 
crustacea. The molluscs are at present in the museum of Cornell 
University, while all the other groups were presented to the United 
States National Museum in recognition of the very kind assistance 
given by Dr. Vaughan and his associates in identifying them for 
us. About a third of the molluscs were new species, and, as prac- 
tically none of Gabb’s species had been figured, every effort was 
made to illustrate all the species as beautifully and accurately as 
possible, more than five hundred and eight figures being given in 
the writer’s report in the Bulletins of Paleontology. 
As a result of these faunal studies and of the very careful 
sections obtained along the various rivers where the fossiliferous 
*See Quart. Jour. Geol. Soc., London, 1850, 1853. 
2 SDiileg, SDs 
