200 



SCIENCE 



[N. S. Vol. XL. No. 1023 



been seeping througli iie superficial horizontal 

 deposit for a very long period, and have formed 

 more or less definite channels or pipes along 

 lines of least resistance. In some cases these 

 pipes have evidently enlarged themselves 

 locally to chimneys several feet in diameter. 



At pit number ten, in which the human re- 

 mains vrere discovered, the asphalt deposit con- 

 sists of two pipes or chimneys connecting with 

 surface flows above. The chimneys arise be- 

 low from a large dome-shaped asphaltic reser- 

 voir. This dome may be an old surface pool 

 now buried and forming a part of the passage- 

 way for further upward movement of oil; or 

 it may be an enlargement of a chimney that 

 was originally very much smaller. 



The asphalt in the chimneys and in the 

 dome in pit ten was largely a soft, viscous 

 mass containing a high percentage of sand, 

 and including in some regions many angular 

 lumps of hard, weathered asphalt. The con- 

 tents of the chimneys are entirely unlike the 

 surrounding soil or rock. The material 

 through which the chimneys pass is not homo- 

 geneous, but is composed of approximately 

 horizontal strata of clay, sand and gravel, with 

 a small inclusion of asphaltic material in most 

 places. The contact between the chimneys and 

 the matrix through which they pass was every- 

 where sharply marked. 



The sand content of the asphalt in the chim- 

 neys and in the reservoir below is quite uni- 

 form in grain and in distribution through the 

 mass. The sand may have been mingled with 

 the tar by entrance through the upper end of 

 the chimneys or may have been carried up from 

 below. The available evidence favors the view 

 that it came from the sandy layers from which 

 the oil is seeping upward, or through which 

 the oil passes on the way. 



The lumps of hard asphalt embedded in the 

 soft sandy matrix in one chimney are gener- 

 ally of irregular form, and may be much oxi- 

 dized or weathered. They were evidently de- 

 rived from asphalt masses that were oxidized 

 by exposure to the weather for a considerable 

 time. They are not found in the dome below 

 and evidently came into the chimney from 

 above. 



The chimneys in pit ten may have origi- 

 nated through gradual building up of the walls 

 around open pipes connected with the oil- 

 supply below. They may have developed as 

 channels forced through deposits already 

 formed. Regardless of the mode of origin, the 

 chimneys have certainly been passage-ways 

 through which asphaltic materials have moved 

 sometimes up and sometimes down for a period 

 of unknovni extent. It is not improbable that 

 at one time these pipes were longer than at pres- 

 ent, the surface of the ground being at a rela- 

 tively higher level. Erosion may have carried 

 away many feet of deposits at this point, 

 shortening the chimneys much below their 

 length at an earlier time. If the history of 

 these chimneys is like that of some now open 

 in this region, they may have spilled their 

 contents widely at times, and on other occa- 

 sions, the tar may have receded, so as to leave 

 long empty tubes or chambers. If such a 

 period of recession lasted any great length of 

 time, one would expect the tar around the 

 opening above and adhering to the walls of the 

 tube to be much weathered. 



In various ways, dry, oxidized pieces might 

 be broken off around the vent and accumu- 

 late as angular fragments below. A later 

 rising of the tar would give a mixture of 

 tar, sand and weathered lumps. If the whole 

 chimney stagnated and oxidized for a time, a 

 later outbreak of oil or asphalt following along 

 the side of the old channel would give two 

 parallel pipes filled with somewhat different 

 materials. 



As nearly as one can judge from observa- 

 tions available, the north chimney had a varied 

 history presenting stages like most of those 

 discussed as possibilities. The south chimney, 

 containing only soft, sandy asphalt, evidently 

 had a more uniform history or a shorter 

 history. 



Remains of Animals Found in the Pit Con- 

 taining Human Remains 

 Bones of birds and mammals were abundant 

 in both chimneys. In the south chimney, 

 which is wide above and narrows sharply be- 

 low, large bones are found only above the nar- 



