38 Calvin on the (Deep Well at Washington, lotva. 
itself and live successfully in the midst of a growing colony of 
Acervularia. To have lived in other genera of corals or in soft 
sediment would have required still different adaptive modifica- 
tions. There is therefore little impropriety I hope in calling the 
worms of our new species Twisted in=dtvellers of Acervularia. 
Iowa City, Iowa, 1)ec. yth^ i88j. 
NOTES ON THE FORMATIONS PASSED THROUGH IN 
BORING THE DEEP WELL AT WASHINGTON, IOWA. 
BY PR0FP:SS0R S. CALVIN. 
The deep well at Washington, Iowa, is located in the eastern 
edge of the city. From the surface to a depth of 350 feet the 
boring passed through superficial deposits of drift and modified 
<lrift. There were beds of gravel, sand, and clay, presenting 
the usual characteristics observed in the regions of modified 
drift in Iowa. The blue clay, so widely distributed in all the 
drift-covered portions of the Northwest, occurs conspicuously 
in the deeper borings from the superficial deposits. 
The "forest bed" was reached at a depth of 1 15 feet. Peaty 
matter with the usual accompaniment of pieces of wood and 
twigs of trees were brought ujd from this depth. By all means, 
however, the most interesting specimens obtained from the 
-"forest bed" were ten small cones, evidently cones of the black 
spruce, Abies nigra. This, so far as I now recall, is the first 
timt the fruit of the old interglacial forest trees has been ob- 
tained in this state. The species indicated by the cones is sug- 
gestive of climatic conditions somewhat more rigorous than 
those which now obtain in the latitude of Washington, Iowa. 
A dark shale, more or less calcareous in some of its layei's, 
was encountei'ed from 350 to 432 feet in depth. This probably 
represents the lower part of the Kinderhook beds, as this forma- 
tion is defined by White, Geol. of loiva, 1S70. About three 
miles west of the point where the boring in question is made, 
rocks of the age of the Upper Burlington limestone occur 
near the surface and are quarried somewhat extensiveh' for 
building purposes. At the well the Burlington and part of the 
Kinderhook slates had been removed prior to the deposit of the 
