I'hiiKilioii SIrrdiH /'iidcj/. L'.")!) 



the fairly ooninion typos of strosiin piracy as phases of sircam adjust inciil. 

 'rii(> ideas itroscntod are probably not new. hut they ate <(iii\ ciiiciit ly lii(piii,'lit 

 lo^clii.T and fairly ch-arly stated and dilferentiatrd. Tli.' liiriM- types of 

 piracy hri<'tly ai'e the lieadward erosion type, the sulilerraiiean lyiie. and 

 tiie iiianation type. The main body (tf tlie pai>er deals with the details of 

 the planation type of piracy. Following the method chosen by the writer 

 as the most satisfactory method in presentin;; a physiot;iai>hic subject, a 

 complete view of the area is j^iven before the details of the main subject are 

 presented. The jjeographic position, the topo}j;raphic condition, the perti- 

 nent fjeolofjio factors and the physiosraphie development of the area are 

 liresented in order before the details of the stream piracy are undertaken. 



rianation piracy consists of the diversion of tiie upper portion of a 

 stream by the invasion of its valley by the lateral planation of a neinh- 

 borinj; stream. Tsually the diverted stream is a minor stream and the 

 pirate stream is much larjier and is widening its valley by lateral plana- 

 tion. The case dc^scribed is that of Cut-off Creek in southern Monroe 

 County. Indiana, a short distance east of Harrodsbnrg. It is shown that 

 till' topographic condition of the area, the cour.ses of the streams con- 

 cerned, and the passage of glacial waters down the ctmrse of the master 

 stream (though the area is distant from the glaciated portion of the 

 state), were important factors favoring the development of the piracy. 

 The principle of static rejuvenation is applied to the diverted and revived 

 rpper Cut-off Creek. It is shown that the rejuvenation of the stream basin 

 brou.ght about l)y its diversion gave opportunity for further piracy to take 

 place; but pirac.v of the headward erosion type. The upper, diverted part 

 of the parent stream lias grown at the expen.se of the lower part. 



I'lanation stream piracy is rather common. An excellent example is 

 shown on the I.,ockport. Kentucky. Quadrangle, where Kentucky River has 

 invaded the drainage basin of Cedar-Sawdridge Creek and diverted that 

 stream S(»me three and one-half miles above its former entrance into the 

 main stream. The lower portion of the divided valley is occupied by I'oiid 

 Creek, a stream far too small for the size of the valley. Judging from 

 the present gradient of Cedar-Sawdridge Creek, this stream at the time of 

 its diversion was approximately tU) feet higher than Kentucky Uiver at 

 the place of diversion. The old valley at the divide between Pond Creek 

 and the .small reversed stream that is etching its way into the I'ond 

 Creek .system is approximately (>(> feet above the Kentucky River. A 

 potential case of planati(m piracy is shown on the Buckliorn, Kentucky. 

 (,)uadrangle. which in many respects resembles Cut-off Piracy. Mace Fork 

 Creek, like Cut-off Creek is small. It will be divided into approximately 

 e(|ual i>arts. or rather far up stream. When the Kentucky River finishes 

 culling the narrow divide between Mace Creek valley and its own valley. 

 the I'piKM- part of Mace Creek will enter Kentucky River as a waterfall 

 aipproximately 110 feet high, a fall similar to the fall of the newly diverted 

 Ippi'r Cut-off Creek. Salisbury, and Atwood !> Professional Paiier No. 

 00. r. S. (Jeol. Surv.. call attention to Couler Valley North of DubiKpie. Iowa, 

 which is described as the former line of the discharge of Little Ma(pioketa 

 River, which stream was diverted principally by the planation of the 

 Mississippi River. Bowman* has described a case in detail along the Huron 



*Isaiah Bowman, "A Typical Case of Slroaiii-Caiiturc in >fii-lii^r;ni". .Tinniial 

 of Geology, Vol. XI, pp. 326-334, 1904. 



