June 17, 1887.] 



SCIEN'CE. 



595 



est discrepancies apparently occur, it is found, 

 that, by tracing the development of each branch 

 of Pueblo art by means of its own internal evi- 

 dence of the successive periods of growth through 

 which it has passed, we establisli its continuous 

 evolution from the simplest beginnings. Mr. W. 

 H. Holmes has clearly shown how the ceramic art 

 of these peoples has naturally developed from the 

 simplest sources, and such as were more or less 

 common to most of the American aborigines in a 

 comparatively low stage of culture. In the case 

 of their architecture, a similar derivation from 

 very primitive forms can be traced. The builders 

 gradually learned to utilize their environment, 

 and perfect the system, until it culminated in the 

 many-storied fortress-pueblo of a single building 

 (such as the ruined pueblos of the Chaco) ; yet 

 these highest achievements of their art in build- 

 ing contain within themselves a record that these 

 people at one time dwelt in simple circular lodges, 

 such as were common to many American tribes at 

 the period of their discovery, 



Victor Mindeleff. 



GEOLOGY OF NEW JERSEY. 



Under the wise and efficient management of 

 Professor Cook, the very modest annual appropri- 

 ation of the geological survey of New Jersey is 

 made to yield, year by year, substantial contribu- 

 tions to the geology of the state. The report for 

 1886 shows that the admirable topographic survey 

 of New Jersey, carried on by the state in co-opera- 

 tion with the U. S. geological and coast and geo- 

 detic surveys, is approaching completion. It is 

 being published on a scale of one mile to the 

 inch ; and the sheets for the northern part of the 

 state, which were issued some time ago, have 

 been generally accepted as the finest piece of carto- 

 graphic work, for so large an area, that has been 

 done in this country. They are in constant de- 

 mand for all the uses requiring an accurate hori- 

 zontal and vertical delineation of the surface of 

 the country, from laying out water-works and 

 railroads to arranging bicycle tours. 



In view of the substantial benefits already ac- 

 cruing from this map before its completion, the 

 wisdom and practical importance of such work 

 cannot be questioned ; and it is to be hoped that 

 other states wUl hasten to profit by New Jersey's 

 enlightened example. 



The results of this topographic survey are to be 

 used, on a reduced scale, as the basis of a new 

 geological map of the state. 



In the purely geological part of this volume, 

 Dr. Britton's chapter on the crystalline or primi- 

 tive rocks of New Jersey occupies a prominent 



place. Three conformable groups are recognized : 

 1. Massive group, composed chiefly of indistinctly 

 bedded syenitic and granitic or gneissic rocks, and 

 probably equivalent to the Ottawa gneiss or lower 

 Laurentian of Canada ; 3. Iron (magnetite) bear- 

 ing group, embracing a great variety of gneissic 

 and schistose strata poor in white mica, sparry 

 limestone and dolomite, with graphite and serpen- 

 tine, and bedded deposits of magnetite, franklin- 

 ite, and other ores (this group agrees well with the 

 Grenville series or upper Laurentian of Canada) ; 

 3. Gneissic and schistose group, including biotite 

 and garnetiferous gneisses, mica, hornblende, talc, 

 tremolite, cyanite, chlorite, and other schists ; vein 

 granite, bedded diorite, and impure limestone and 

 serpentine. This group resembles Dr. Hunt's 

 Montalban system ; and, since it is conformable 

 with the iron-bearing group, the view is advanced 

 that the Montalban may be simply an upper divis- 

 ion of the Laurentian. It is interesting to note 

 here that other students of the great Appalachian 

 belt of crystalline strata have been led to propose 

 more or less similar re-arrangements of the crys- 

 talline terranes, all of which goes to show the ex- 

 tremely unsettled state of eozoic geology. Dr. 

 Britton introduces a series of sections to show that 

 the same conformable sequence of his three groups 

 obtains in all parts of the highland district ; but 

 in view of the massive character of the first group, 

 and the general paucity of outcrops at critical 

 points, this view can scarcely be regarded as defi- 

 nitely established. 



It has long been known that the rocks of the 

 highlands, like those of the Appalachian belt gen- 

 erally, are involved in a series of closely appressed 

 folds the axial planes of which are usually inclined 

 at a high angle to the south-east. This report, 

 however, brings out more clearly than ever before, 

 another important feature of these folds ; viz., 

 that their axes are not horizontal, but are inclined 

 at an average angle of thirty degrees to the north- 

 east. Since the pitch of the folds is always in the 

 same direction, this involves a series of transverse 

 faults with the uplift on the north-east ; and more 

 or less important examples of such faults have al- 

 ready been observed, especially in the iron-mines. 



Among the paleozoic strata of this region, none 

 are more interesting, or have proved more puz- 

 zling to geologists, than the red conglomerate and 

 associated limestone and slate composing the Green 

 Pond Mountain Eange. In the earlier reports of 

 the survey these were referred to the Potsdam, 

 Trenton, and Hudson River groups. The later in- 

 vestigations, however, have resulted in the accu- 

 mulation of proof, both stratigraphical and paleon- 

 tological, that these rocks belong much higher in 

 the scale ; the red conglomerate being the equiva- 



