IO THE SAUROPOD DINOSAUR BAROSAURUS MARSH. 
The rock consists of clay with the very finest silt, the grains of which are probably 
not more than .01 mm. in diameter. A fine grit was discernible in the clay, and an 
appreciable content of lime, as shown by a vigorous effervescence with acid. The gray 
clay shows occasional rusty stains from recent weathering, probably due to the presence 
of ferrous carbonate. 
The inferred habitat was a rather swampy flood-plain, as water and organic matter 
must have been present to hold the iron in ferrous condition. Black specks which con- 
tained no grit seem to indicate plant material. These could not have been bone particles, 
as the bone is decidedly gritty; on the other hand, the decaying animal carcass may 
have been the source of the organic matter. 
Material 
The whole Barosaurus lentus individual must have been present originally, but was 
subject to dismembering and intermingling of the bones, possibly by carnivores, as the 
presence of the tooth might imply, even though there is no indication of tooth scoring 
on the Barosaurus bones. On the other hand, the confusion of the bones may have 
been due to the working of the entombing material in time of excessive moisture. 
The bones are rarely injured other than by an oblique crushing, and some of the 
thinner lamina and processes are delicate indeed. They lay scattered, although several 
dorsals were together at one end of the quarry, while the cervicals were at the other. 
It is entirely possible that the bones which are missing may have been lost by subsequent 
erosion, and that the specimen represents a single complete entombment, with a very slight 
intermingling of other bones {Barosaurus affinis, see below, page 38). 
The material consists therefore of three specimens : 
Barosaurus lentus Marsh, holotype. Yale Museum catalogue number 429. Of this 
specimen the following identified elements are present : 
Cervicals 12-15 4 
Dorsals 1, 4, 5, 7, 9, 10 6 
Caudals 2-6, 13, 15-17, 19-20, 23, 25, 28, 32, ca. 42 and 70, also fragments ca. 12, 13 19+ 
Chevrons 5, 9, 16 3 
Many ribs and rib fragments ca. 10 
Sternal, left 
Scapula, part 
Sacrum, part of centrum and coalesced neural spines 
Portions of ilium 
Pubis, right, part 
Ischium, left, part 
Femur fragments 
Tibia fragments 
Ends of left fibula 
Si± 
Barosaurus affinis Marsh, holotype. Yale Museum catalogue number 419. Of this 
species there are present : 
Metacarpals 2 
Theropod dinosaur, gen. et sp. indet. Yale Museum catalogue number 415. 
Tooth 1 
