182 



SCIENCE 



[N. S. Vol. LII. No. 1338 



ance of the germinal epithelium, however, has 

 been noted in case of ligation of the vas 

 deferens without further disturbance of the 

 testis. The testis graft does persist after 

 transplantation in a female, with an intact 

 ovary, and it is as normal as autoplastic tes- 

 ticular grafts, either with or without previous 

 castration. 



These observations show definitely that a 

 sex gland can be successfully transplanted to 

 an animal of the opposite sex which retains 

 one normal gonad. Positive cases are of 

 much more significance than any ntunber of 

 negative cases and leave no question as to 

 whether the two glands can exist in a func- 

 tional condition within the same organism at 

 the same time. A male rat with one testis will 

 function as a normal male during the time it 

 is carrying two ovarian grafts as an integral 

 part of its somatic structure; both of these 

 grafts remain essentially normal, showing all 

 grades of maturity of follicles, even after ex- 

 istence, in the subcutaneous tissues of the 

 m-ale, of eight and one half months. 



A discussion of these observations will be 

 taken up more fully when the completed work 

 appears. 



Carl E. Moore 



The University or Chicago 



STATIC REJUVENATION 



For several j'ears the writer has been 

 making a systematic detailed study of the 

 driftless area of southern Indiana, and has 

 now in preparation a paper on the physio- 

 graphic development of the Knobstone cuesta 

 region lying between the Muscatatook and 

 Ohio rivers. This particular region offers one 

 or two problems of more than local interest, 

 and the interpretation of one of these will be 

 briefly stated here. 



It appears that some time about the middle 

 of the Tertiary the entire region was reduced 

 to a peneplain (Highland Eim, or Lexington 

 peneplain). The region was then rejuvenated 

 by uplift. Dissection of the uplifted pene- 

 plain followed. Dissection was fairly com- 

 plete near the major streams, and, in the 

 regions of soft rocks, local areas were reduced 



to base-level. These locally reduced plains 

 indicate that the uplift amounted to some- 

 thing like 175 feet. The region was again 

 uplifted and dissection was refiewed or con- 

 tinued. The Tertiary uplifted peneplain is 

 now represented by remnants which are as 

 much as 300 to 500 feet above the present 

 local base-level. The liTew Albany shale and 

 the lower part of the Knobstone areas were re- 

 duced to a lowland in contrast to the region 

 west of the Knobstone escarpment. The low- 

 land plain, stretching north from Louisville 

 consists of a flat to undulating plain varying 

 from 430 feet in the valleys near the Ohio 

 River to something like 600 feet in elevation 

 on the low divide between Silver Creek and 

 the tributaries of the Muscatatook Eiver. 

 Since there are a large number of hills and 

 flat interstream tracts at an elevation of about 

 500 feet at the south and coming up to about 

 600 feet near the above mentioned divide to 

 the north, it has been stated that a local pene- 

 plain was formed at that level.^ The writer 

 concurs in the belief of a base-leveled plain 

 of local area, and that its further development 

 was terminated by rejuvenation. The re- 

 juvenation, however, was not necessarily 

 brought about by uplift. The dissection of 

 the plain was very likely brought about by 

 drainage changes made near the beginning of 

 the Pleistocene. The present Ohio Eiver is a 

 large stream made up of a number of former 

 drainage basins which were more or less 

 destroyed or deranged by combination into a 

 large major stream approximately skirting 

 the outer limits of glacial advance. A very 

 much smaller stream than the present occu- 

 pied this territory near Louisville. It was 

 able to reduce the area of soft rocks nearly to 

 base-level, but it had a much steeper gradient 

 than the much larger present Ohio. When 

 the present Ohio invaded the basin of the 

 much smaller pre-g'lacial stream the local 

 peneplain was statically rejuvenated, due to 

 the sinking of the larger stream into the plain 

 on account of its ability to possess a much 

 lower gradient in its grade condition. Such 

 1 Chas. Butts, ' ' Geology of Jefferson Co., Ky., ' ' 

 Ky. Geologdoal Survey, 1915, pp. 201-203. 



