Archaeological Investigations in Jefferson C ounty, Mo. 191 
in the isometric drawing (See Plate X A). The first clue in- 
dicating that we had an old gully bank to consider was given 
by the presence of stone artifacts without pottery accompanying 
them at the floor area marked D in the old silt area along the 
northwest edge of the shelter. The change in excavational tech- 
nique has since borne out our theory. 
When did the erosion period that cleaned out the earlier silt 
fill occur ? It may have taken place when there was far greater 
rainfall than at the present time. This erosion period might 
possibly prove to tie in with the post glacial pluviation men- 
tion by Dr. E. Antevs as occuring some 3000 years ago. 
The oldest occupations of this rock shelter contain very 
long projectile points with expanding stems, elongated S shaped 
edges and concave bases, a long curved blade and large disc 
scrapers (Plate X B) with a single flaked surface on one face 
found in loose sand that covered the original sand floor of the 
shelter before silt had begun to fill the shelter. 
Crushed charcoal and soft animal bones too fragmentary 
to be identified were also found. These lay on the sand floor 
except in the area where the underground stream issues from the 
rock shelter under the overhang where objects of several oc- 
Cupations and differing ages are found mixed together, and in 
localized pockets in the center of the shelter where the later 
shelter fill penetrates to the original sand floor. The implements 
are invariably stained by iron precipitate leached out from the 
layer above them and re-deposited. All are more or less dehy- 
drated in spite of the moist conditions in which they were found. 
At more shallow levels within and along the northeast and 
southwest flanks of the shelter in the first silt fill were found 
two small circular fireplaces consisting of charcoal. The one 
at the south end of the shelter lay at a considerable depth (See 
Plate XI A), below large fallen blocks from the shelter roof. 
No animal bones or stone implements were found near this 
fireplace. The other fireplace at the northwest end had stone 
1Antevs, E. “The Archaeology of Pleistocene Lake Mohave,” South- 
west Museum Papers, No. 11, p. 48. 
