Pytheas, the Discoverer of Britain Author(s): Clements R. Markham Source: The Geographical Journal, Vol. 1, No. 6 (Jun., 1893), pp. 504-524 Published by: geographicalj Stable URL: http://www.jstor.org/stable/1773964 Accessed: 20-02-2016 06:28 UTC Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at http://www.jstor.org/page/ info/about/policies/terms.jsp JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact
[email protected]. Wiley and Royal Geographical Society (with the Institute of British Geographers) are collaborating with JSTOR to digitize, preserve and extend access to The Geographical Journal. http://www.jstor.org This content downloaded from 132.174.255.116 on Sat, 20 Feb 2016 06:28:03 UTC All use subject to JSTOR Terms and Conditions 504 PYTHEAS,THE DISCOVERER OF BRITAIN. the two resultswould be simultaneous; so the questionof relative age will not come in. With regard to tarns in rock basins, these only occur under most favourable circumstances,where ice may have been expected to have had great erosivepower. Now, the argument of my earlier papers was, that if glaciers do excavate, they should make tarns at intervals down the valley. Dr. Blanfordforgot that mud from glaciersdoes not prove erosion,but only abrasion,a distinctionwhich I have drawn; and I quite agree with Mr.