32 The American Geologist. January, leos 
the museum, and especially known for his successful 
palaaontological explorations in Patagonia and Montana. 
It was especially desired to secure a complete skeleton of 
some of the great plesiosaurs which are known to have in- 
habited the region west of the Missouri river during Creta- 
ceous times. Continuing his v/ork of 1902 and 1903, Mr. 
Brown made special search in the Pierre shales, with satis- 
factory results. From these shales near Edgemont, S. Da- 
kota, he obtained the greater part of a plesiosaur skeleton, 
including skull, jaws, the complete neck about fifteen feet 
long, one complete paddle, part of the pectoral girdle, and 
some dorsal vertebrae. In the same locality there was se- 
cured another plesiosaur having skull, jaws, one complete 
paddle, and some vertebrae. Two other important reptilian 
specimens were obtained in this formation, a young plesio- 
saur having both girdles and two paddles ; and a mosasaur 
with skull, jaws, and part of the skeleton uncrushed. This 
formation yielded twenty-two boxes of fossils. 
Mr. Brown extended his exploration into the Ft. Ben- 
ton formation. In 1903 he found there a complete skull of 
a great marine crocodile with a long snout, in a somewhat 
broken condition. This year a perfect specimen of the same 
animal was secured. 
In beds near the Judith river in Montana the skele- 
ton of a large hadrosaur named Trachodon was discovered, 
including pelvis, vertebral column, and limb bones. 
Mr. Brown with his party then journeyed into New 
Mexico in search of beds which had been reported as con- 
taining large reptiles of the Jurassic age. On arrival it was 
found however that these beds were really of Cretaceous 
uge, belonging to the Laramie. Here were fortunately ob- 
tained the complete skull and jaws of one of the primitive 
horned dinosaurs named by professor Cope Diclonius ; also 
a large turtle. 
From New Mexico Mr. Brown went into Arkansas and 
made search in ac revasse, explored somewhat last year, for 
fossil mammals of the Pleistocene period. Here were secured 
ten complete skulls and many fragmentary skulls of rodents 
and carnivores, about one thousand jaws, thousands of limb 
bones and vertebrae, representing nearly forty species of 
animals. Materials were brousrht to the museum for the 
