Decebiber 27, 1901.] 



SCIENCE. 



1011 



length. The coecal tubes, which Dr. Sollas has 

 shown to be probably organs of tactile impres- 

 sion, were wanting in the errantian forms, 

 more or less abundant in those moving freely on 

 a fixed pedicle, and in those fixed by the lower 

 valve, abundant, and in Crania even branching. 

 He described the external glands of Terebra- 

 tulina, as well as the strand-like bundle of 

 sperm cells. He insisted that the Heart of 

 Hancock was not a pulsating organ, and was 

 inclined to believe that the ' accessory hearts ' 

 were genital in their nature. 



Glover M. Allen, 



Secretary. 



DISCUSSION AND CORRESPONDENCE. 

 CONNECTICUT RIVERS. 



In the issue of Science of November 29, 1901, 

 Professor W. M. Davis reviews my paper on 

 '■ The River System of Connecticut ' {Journal of 

 Geology, IX,, 1901, pp. 469-485) and expresses 

 his doubt respecting the principal thesis of the 

 paper ; namely, that Connecticut rivers betray 

 by their orientation a controlling influence of 

 joint or fault planes. The subject of stream 

 orientation is a large one and the explanation 

 offered a somewhat new one for American rivers 

 at least. The thesis is one not easily demon- 

 strated as respects the larger area treated, and 

 the review seems to me to be in the main an 

 eminently fair one. From it I infer, however, 

 that my paper may in some particulars be sus- 

 ceptible of misinterpretation, and, therefore, 

 take this opportunity to correct certain impres- 

 sions which appear in the review, so as, if possi- 

 ble, to prevent further misunderstanding. 



If I have omitted to speak at length of the 

 particular controls of stream orientation other 

 than by joint and fault planes, it has not been 

 because I would ascribe little importance to 

 them, but because in a general paper dealing 

 with a special kind of control it was obviously 

 impossible to treat all at length. On page 474 

 it was stated : 



"It is not to be expected that the actual 

 course of a stream will now be coincident with 

 or even absolutely parallel to any fault direc- 

 tion, for there have unquestionably been many 

 local conditions which have produced larger or 

 smaller migrations of the river channels. Their 



general direction has, however, it would seem, 

 been maintained despite the minor accidents 

 which have marked their life histories, and even 

 under so revolutionary a change as complete 

 reversal of drainage." 



I should certainly agree with Professor Davis 

 when he says that, "it is inherently improbable 

 that the Pomperaug fault lines possess an ex- 

 tension all over the State in systems so rigid as 

 are here postulated." And it was a matter of 

 some surprise to me when the natural trough 

 lines were found in so many instances to cor- 

 respond to known fault directions of the Pomp- 

 eraug Valley. Some explanation of this may, 

 however, be found in the fact that the lines 

 noted for the master streams of the State cor- 

 respond in direction, not to the prevailing faults 

 in the Pomperaug Valley, but rather to the ex- 

 ceptional ones. In the Shepaug Valley imme- 

 diately adjacent to the Pomperaug, however, 

 the only control observable is from the four 

 directions of faulting which ijrevail in the Pomp- 

 eraug Valley. It is my anticipation that when 

 the theory is applied in detail to the broader 

 area of the Connecticut Valley, and the direc- 

 tions of streams carefully compared with the 

 directions of the actual minor as well as major 

 faults of that Newark basin, a control will be 

 recognized to have gone out from the planes of 

 faulting. That the directions which were dis- 

 covered in the Pomperaug Basin will be found 

 to be the only ones I do not of course expect, 

 and it is quite likely that in certain areas they 

 may not appear at all. That an elaborate sys- 

 tem of joints and faults, analogous to that of 

 the Pomperaug Valley exists and is accountable 

 for the zigzag outlines of the trap hills scattered 

 over the Connecticut Valley seems to me, how- 

 ever, hardly to admit of doubt. That such a 

 system ceases to exist beyond the border of the 

 Newark is, in my view, inherently improbable. 



I should be the last to wish to push the theory 

 of control of streams by fault and joint planes 

 beyond what the facts warrant. In the Pomp- 

 eraug Valley itself the faults supposed to con- 

 trol the drainage were in the majority of in- 

 stances discovered. In the near-lying area, 

 e. g., the Shepaug river basin, where the rivers 

 adhere to the four prevailing fault directions of 

 the Pomperaug Valley, this explanation seems 



