May 29, 1896.] 



SCIENCE. 



819 



mentioned the curious outliers of {'ambrian and 

 Ordovician strata that have been discovered 

 far up in the mountains from the main outcrops 

 that sliirt them. They lie in valleys in meta- 

 morphosed crystalline rocks, which valleys rep- 

 resent beyond question the old pre-Cambrian 

 river valleys and which were filled with sedi- 

 ment by the encroaching sea of Cambrian and 

 Ordovician time. Lake George is the largest 

 example of this kind and contains remnants of 

 Potsdam sandstone and Trenton limestone in 

 its southern portion. The valley of Trout 

 Brook, which lies just west of Rogers' Rock, at 

 the north end of Lake George and that is sepa- 

 rated from it by a high intervening ridge of 

 gneiss, contains two outliers of Potsdam sand- 

 stone of a few acres in extent. In the valley of 

 Putnam's Pond, in the western part of Ticon- 

 deroga township, there is another outlier of 

 Potsdam sandstone. Both of these are shown 

 on the map of Ticonderoga which accompanies 

 the speaker's report to Prof. James Hall on 

 this region, and which was published in 1895. 

 Another isolated area of calciferous limestone 

 is found on Schroon Lake, under Schroon 

 Lake post office. It is a few acres in extent 

 and the exposed rock is about 75 feet thick. 

 It is about 350 feet above tide at its upper 

 point. Down the lake and river valley it is 

 nearly forty miles to the next Cambrian out- 

 crop, which is below Hadley. The speaker 

 also cited the little outlier of Trenton limestone 

 near Wells, on the Sacondaga River, and the 

 fact that the Cambrian and Ordovician sedi- 

 ments on the west side reach short distances 

 into the areas of crystalline rocks and along 

 the river valleys. He stated that all the out- 

 liers on the east side had a uniform north- 

 easterly strike and a dip of 10 to 20 degrees to 

 the northwest. He remarked that they oc- 

 curred in the valleys of streams which are 

 notably sluggish, explaining their slow move- 

 ment by the fact that they flow in pre-Cam- 

 brian valleys, already nearly reduced to a base 

 level. He referred their parallel strike and 

 dip to the general warping of the surface in 

 this region. Remarking the undoubted presence 

 of faults in the later development of the topog- 

 raphy he emphasized the evidence of this early 

 erosion long before the time of fossiliferous 



sediments. He added that the old river valleys 

 had in part been determined by the presence of 

 crystalline limestones. The paper was discussed 

 by Messrs. Dodge and Hovey. 



The last paper of the evening was by L. M. 

 Luquer and H. Ries, and described an area of 

 Augen-gneiss near Bedford, N. Y. It was read 

 by Mr. Luquer, and will appear in full in the 

 Transactions .The gneiss appears to have been 

 originally a granitic rock that has been exten- 

 sively crushed and sheared out into the augen 

 structure. The original quartz has been mostly 

 comminuted, but the Carlsbad twins of ortho- 

 clase have remained as augen. 



The paper was discussed by Dr. E. O. Hovey, 

 who cited the case of the sheared Eisenach 

 quartz-porphyry in which the feldspars have 

 been crushed, but the quartzes have been drawn 

 out. 



Mr. G. F. Kunz mentioned the following 

 items as the meeting closed : 



A meteoric stone weighing 31 ounces was 

 seen to fall by Mr. J. F. Black, April 9, 1896, 

 at 6:15 P. M., on his farm 9 miles east and one 

 north of Ottawa, Kansas. This meteorite con- 

 tains iron particles throughout and is of the 

 characteristic stony variety. 



A remarkable nugget of native silver weigh 

 ing 448 ounces troy, was lately found five miles 

 from Globe City, Pinal county, Arizona. The 

 mass is a water- worn nugget, slightly oval, very 

 compact, and on its surface is bright silver- 

 white, showing that it is made up of strings of 

 crystallized silver, whereas the interior of the 

 entire mass contains more or less cerargyrite. 

 It has been presented to the Lea Collection of 

 American Minerals of the United States Na- 

 tional Museum. 



New Zealand promises, mineralogically, to 

 be a country of surprises, and many interesting 

 things are gradually being brought to light by 

 the agate hunters from Oberstein, Germany, 

 who are visiting it. Recently they have dis- 

 covered some immense masses of rolled, 

 rutilated quartz, weighing from 10 to 30 pounds 

 each. The masses are penetrated by crystals 

 of rutile, red, brown and yellow, many inches 

 in length and of the fineness of hair. Occa- 

 sionally the rutiles occur very sparingly ; then 

 again they are in such profusion as to give the 



