June 9, 1893.] 



SCIENCE. 



317 



division takes a second one of the five methods, and so on till 

 each has had them all. Lecture and laboratory exercise have 

 helped each other. Each one understands the subject and is pre- 

 pared to enjoy and profit by the more careful measurement of 

 specific gravity with delicate balance and corrections for varia- 

 tion of temperature and pressure from standard conditions, that 

 awaits him in his term or two of advanced practical work. Such 

 a course prepares him fully for the higher grade of work, so that 

 neither inherent difficulties or imperfect explanation can now be 

 a bar to progress. 



It must be admitted that the method presented involves some 

 additional effort on the part of the instructor, but there is abun- 

 dant compensation in the superior results obtained. If space 

 permitted, I would add something concerning methods of secur- 

 ing at small expense the duplication of apparatus necessary to 

 keep the laboratory studies in close connection with lecture and 

 classroom work, but that would better be reserved for another 

 occasion. 



DISCOVERY OF ANCIENT ARGILLITE QUARRIES ON THE 

 DELAWARE. 



BY HENRY C. MERCER, DOYLESTOWN, PA. 



The discussion of the Trenton gravel specimens has forced 

 several important questions upon our attention. Where did the 

 argillite come from with which the chipped objects were made? 

 Granted that much of it was found in the river-bed in the shape 

 of boulders and erratic blocks, whence had this material been 

 transported by the river? 



To learn that modern Indians on the Delaware quarried jasper 

 and in the process of blade-making strewed the quarry site with 

 '■ wasters," resembling in form the Trenton specimens, was to 

 ask whether they also quarried argillite. 



We had found argillite "turtle-backs" on the surface at the 

 camp-sites of Gilmer's Island, Gallows Run, Ridges Island, and 

 Lower Black's Eddy on the Delaware, but they lacked the final 

 and convincing association with the quarry to prove their pedi- 

 gree, and we still sought the whereabouts of the ancient pits, the 

 refuse heaps, and the "rejects " or blocked-out implements which 

 were to repeat in the now famous blue stone, the story of the 

 inchoate blades of jasper. 



The way towards an answer to one of the vital questions that 

 concerns the antiquity of man in the Delaware valley was opened 

 on May 32, by the discovery by me of a series of seven or eight 

 depressions surrounded by masses of argillite chips (a quarry in 

 fact with all the surface characteristics of Macungie, Vera Cruz, 

 and Durham, in America, or Grimes Graves, or Spiennes, in Europe) 

 on the steep north slope of the hillside at Point Pleasant, Bucks 

 County, Pennsylvania, on the right bank of Gaddis' Run, about 

 one-quarter mile above its mouth and half a mile from the well- 

 known Indian camp-site at Lower Black's Eddy. The work of 

 carefully clearing out one of the depressions and trenching its 

 refuse heap was begun yesterday afternoon and will occupy an 

 indefinite time. 



Notched in the slope whose angle is about 35 degi-ees, the de- 

 pression, one of eight or nine others, fronts a solid ledge of argil- 

 lite (an outcrop of the large vein here traversed and exposed by 

 Gaddis' Run, and twice tapped near by, by modern quarries as 

 the purest source of the material). 



Its largest diameter is about thirty feet, its depth five, and 

 breadth eight. The trench begun across its narrowest width, 

 penetrating for three feet through loose yellow mould, has shown 

 as yet nothing of importance beyond two bits of charcoal and 

 broken (quartzite pebble) hammer-stones at a depth of one and 

 one-half feet. Another excavation about three feet in diameter 

 has entered the mass of refuse for four feet vrithout reaching its 

 bottom, and discovered at various points thirty-three " turtle- 

 backs," twenty-five broken bases or points, and four hammer- 

 stones. On the surface about the other pits I gathered in a few 

 hours twenty " turtlebacks," six ends or points, and fourteen 

 hammer-stones. 



With the work of penetrating to the bottom of the refuse, and 

 studying the ancient quarrying process scarcely begun, I have 



hardly had time to more than think of the important questions 

 suggested : Who made and worked the quarry ? Will ii; show a 

 successive series of occupations? Can it be connected with the 

 village site at Lower Black's Eddy? What shall we say of these 

 rudely chipped forms? Are they "wasters" and do they of all 

 " wasters " yet beard of, resemble the Trenton specimens ? 



We are twenty-five miles above Trenton and at the largest and 

 purest outcrop of argillite on the right river bank above that 

 place.' The bed of Gaddi.s' Run and the river-shore below its 

 mouth are thickly strewn with argillite blocks and water-worn 

 boulders — a pathway, in fact, littered with blade material, ex- 

 tending, from the ledge above referred to, to the Indian camp 

 half a mile distant. While the significance of this has been ob- 

 scured by chipped fragments from the modern quarries fallen 

 into the stream, and the stone dressing that has accompanied the 

 building of a dam, two bridges, and a canal aqueduct, there can 

 be little doubt that the inhabitants of the village often went no 

 farther than a few hundred yards along these beaches for their 

 material. 



But too much hangs upon the further examination of this site 

 and the neighboring camp, now at last unfolded to the student 

 in its fuller significance, to warrant a premature word. 



LETTERS TO THE EDITOR. 



(,*^ Correspondents are requested to be as brief as possible. The writer's name 

 is in all cases required as proof of good faith. 



On request in advance^ one hundred copies of the number containing his 

 communication will be furnished free to any correspondent. 



The editor will be glad to publish any queries consonant toith the character 

 of the journal. 



Science Work at the Avalon Summer Assembly. 



I HAVE just received a little blue pamphlet containing the an- 

 nouncement of the new summer school at Avalon, New Jersey, 

 and an extremely interesting and suggestive address on " Science 

 Teaching in the Schools," by Dr. Charles Dolley, its president. 

 Copies of this, I have been told, may be had by writing to Mr. 

 Charles Adamson, secretary, 119 S. 4th Street, Philadelphia, Pa. 

 The objects and methods of this new school are so new and at- 

 tractive that it certainly marks the beginning of a new era in the 

 teaching of science and art in our common schools. 



The keynote of Dr. Dolley's address is struck by the following 

 sentences in speaking of the proper method of educating the 

 coming generation: " They begin by moulding little birds' nests 

 of clay, or constructing cones and cylinders, cubes, and octagons 

 out of paper, without ever having examined a bird's nest, other 

 than that of the sparrow under the eaves, and knowing abso- 

 lutely nothing of the interest to be found in a prism of quartz, a 

 snowflake, or an icicle. They have been taught of the distribu- 

 tion of whales and camels and all sorts of exotic varieties, but 

 are absolutely ignorant and blind to the wonders of nature to be 

 found at their very doors; wonders requiring no text-books, no 

 costly instruments, but which may be investigated by means as 

 simple and inexpensive as the key and kite string of Franklin." 



How few the teachers, let me add, who have the slightest ink- 

 ling as to the wonderful history written in the chalk or slate they 

 daily use! 



Missions and philanthropic societies do good work in this world, 

 but much is wasted. " What is needed," says Dr. Dolley, " is a 

 sanitary missionary in every home, and this we can secure by 

 training the children, by awakening in their minds a desire for 

 something better, for more sunshine, more flowers, a wider hori- 

 zon and more wholesome surroundings." How few the house- 

 keepers who know the slightest whit about the yeast they use, 

 the mother and flowers of vinegar, the moulds on jellies, the 

 cause of rancid butter, or the nature of contagion! 'The tritest 

 things of our mortal experience are the most mysterious.'' There 

 is enough of interest in a mucilage bottle to keep a man studying 

 a lifetime. 



' On Dark Hollow Run (below New Hope) I found a small vein of It nearly 

 two miles from the river. The blue slate in Pidcock's Creek, on the south 

 slope of Bowman's HUl and at the Harvey and Van Hart quarries below Tay- 

 lor'svlUe, lacks the concholdal fracture. 



