3 
Class, CEPHALOPODA 
Sub-class, TETRABRANCHIATA 
Order, Ammonoidea 
Ammonites were collected from the three formations laid down in 
the western Canadian extension of the Pierre sea. These formations are, 
from oldest to youngest, the Pakowki shale ( = Claggett of United States), 
the Bearpaw shale, and the lower marine shale member of the Fox Hills 
“sandstone’* formation. The species found are listed below. 
Species 
Pakowki 
shale 
Lower 
beds, 
Bearpaw 
Upper 
beds, 
Bearpaw 
Lower 
Fox Hills 
shale 
Baculites compressus Say 
? 
z 
X 
r 
Baculites graiidis H. and M 
X 
Baculites crickmayi n.s 
X 
Placenticeras intercalare Meek 
X 
X 
Placenticeras meeki Boehm 
X 
X 
X 
Rha^oceras haUi Meek 
X 
Acanthoscaphites nodosus (Owen) var. brevis Meek 
7 
X 
X 
Baculites compressus probably occurs in the Pakowki shale as reported 
by Dowling^ B, asper Morton has not been recognized, however, nor 
has B. ovatus Say. 
Baculites crickmayi n.sp, 
Plate I, figure 1; Plate II, figures 1, 2, 3 
Fossil in the form of an internal cast. Elongated; of fairly large 
size, and rather rapidly tapering compared with other Baculites. Cross- 
section ovate, tapering toward the siphonal side. Surface of cast marked 
by broad, rounded, arcuate undulations, which commence at the dorsal 
and pass obliquely down and backward in a broad curve, terminating 
abruptly on the ventral-lateral region. 
Septa not crowded, lobes and sinuses deep and divided into somewhat 
divergent, digitate branches. Siphonal lobe about as long as wide and 
provided with two terminal, more or less spreading, branches, each of 
which has generally three, but in some cases two, nearly equal, digitate 
branchlets at the end, and two similar lateral ones on the outer side. 
First lateral saddle two-thirds as wide as long, much narrower than the 
siphonal lobe, and divided at the anterior end into two nearly equal branches 
each of which is subdivided into three or four spreading, digitate branch- 
lets. First lateral lobe nearly twice as long as wide, and divided at its 
end into two nearly equal parts, each with three spreading and digitate 
subdivisions. Second lateral saddle very similar in branches and sub- 
divisions to the first and only a little larger in size. Second lateral lobe 
about as broad, but shorter than the first, and bearing two large, equal, 
iQeol. Surv., Canada, Mem. 93, “Southern Plains of Alberta”, p. 47. 
