Professional Paper No. 14 Se 'es ' er°SraP ly an(l Mineralogy, 23 E, Chemistry and Physics, 37 DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY CHARLES I). WALCOTT, DIEECTOE CHEMICAL ANALYSES OF IGNEOUS ROCKS PUBLISHED FROM 1884 TO 1900 WITH A CRITICAL DISCUSSION OF THE CHARACTER AND USE OF ANALYSES HENRY STEPHENS WASHINGTON W A S III N G T O N GOVERN M K N T l> K I N T I N G OFFICE 11) 0 3 CON TENTS I ettei of tnnsmittil 5 Prelat e 7 Introduction _ n The cVuracter o£ lock -uialvses 13- General considerations lo. Kepresentatneness K> Character of the rock mass It, Amount ot material IS Microscopical examination 1<) Accura< y 1Q Possible eirors _>0 Coiiipletenes« 2 > Mam constituents 24 Minor constituents 25 Eating ot anal\ '-cs 28 Accurac\ 2') Internxl evidence ^0 Agre emcnt \\ ith the mode 30 Summation -j^ Fxternal e\idcnce 3g Methods ^g Indirect e\ idence 3B Completeness =57 Rating adopted in the tables 33 Discussion ol the tables 4 Di \iaion into parts 4^ Part I 44. Part II 4-> Basis ot arrangement ol aualj =es 4f( 4ttempted use ol current pptrogriphu sj^tem 4g Adoption ot the quantitative sjstem 47 Quantit iti\e classification of igneous rocks 47 Constiuction of the sjstem 47 Nomenclature of the system 48 Comparison of old and new nomenclatures 49 4 CONTENTS. Discussion ot the tables Continued Quantitative classification of igneous locks Continued Page Tabular exhibit of divisions and names of quantitative system (5 tables).--...---..... 53 Keasons for anangement according to the quantitative classification .................. 59 Distribution of rocks by new system................................................ 61 Comment on facts expressed by tables.............................................. 62 Various features of the tables .-............................................"... ........ 64 Geographical arrangement.............................. ..................... 64 Numbering ol analyses ........................................................ 65 Eating of analyses .................. ......................................... 65 Results ot rating analyses............................................... ..... 65 Constituents.................................. ............................... 67 Specific gravity ........ ...................................................... 68 Norm ........................................................................ 68 Correspondence of norm and mode.......... .................................. 69 Locality...................................................................... 69 Analyst...................................................................... 70 Reference --.....-----.-.-...............-......-......--.-...-............... 70 Author's! name..-.-.--.......... ............................................ 71 Remarks ..................................................................... 71 Correlation of the qualitative and the quantitative systems................................... 72 From the qualitative point ot view ..................................................... 73 From the quantitative point of view -......--...,.--......--......--..-...-...-.--...... 76 Meteorites......-.....-....-..-.......-......-..........-....-..-...--.-...--...-.--.- 81 Calculation oi center points................................................................ 81 Intioductory ..... .....-...-.--........-...-..-......-----.-.--......--.-..--.-...... 81 Peisalane............................................................................. 84 Perfemane..............-...-.-................--.....--.-...---.-.-.--...-.-.-.....-. 88 Distribution ot magmas and the average rock ............................................... 100 Introductory ..-........-.-.-..-,.......-......-......-......-.-..-..-..-....- ....... 100 The distribution of magmas. -.-......-.....-....-..-.-....-...-..-.--.-..---...----.... 102 The average lock ..................................................................... 106 First method ..................................................................... ' 106 Second method ................................................................... 109 List of abbieviations ..............--.............................-------.--.....--.....-.. 116 Collection ot rock analyses............................ -......-......---.--.--....----..-.. 1-1 Parti............ ................................................................... 121 Part II............................................................................... 371 Glossary ..............................................--......---.....---.-.--.---..--.-. 475 Prefatory note to indexes....-......-......-..-.....--.....---.--.--.---.-.----.-----.----- 481 Index to text............................................................................. 483 Index to new rock names in Part I.........-.-.....-......-.--...--.....-...-.------------- 486 Index to old rock names m Parts T and II........ ...... ........-.-------.-- .-....----... 489 Index to localities in Parts I and II................ .........---------.-.-----.------.----- 493 LETTER OF TIUNSMITTAT, DEPARTMENT OK THE INTERIOR, UNITED STATES GEOLOGICAL SURVEY, ITWm^/Aw, ]). ('., March 20, 1903. SIR: I have the honor to transmit to you a manuscript entitled "Chemical Analyses of Igneous Rocks published from 1884 to 1900, with a critical discussion of the eharae.ter and use of analyses,'' by Henry Stephens Washington, and to recom­ mend that it be published by the Survey as a Professional Paper. This work is pri­ marily a compilation of chemical analyses, and is especially valuable to petrographers and chemists, for it places in one volume material gathered from a great many scat­ tered source's. The critical discussion of the value and use of rock analyses, with comments upon methods of analysis and a review of the bearing of this mass of material upon rock classification, is also of much importance to both petrographers and chemists. The arrangement of the analyses according to the quantitative system for the classification of igneous rocks permits one to compare readily any new analysis with many others of closely allied rocks. A work of this kind is necessarily very expensive when published by a commercial house, and if so issued would be beyond the reach of many who would desire to use it. It is particularly appropriate that the Survey should publish this work, because a very large proportion of the, rock analyses here included have been made in the laboratory of the United States Geological Survey, upon material which is preserved in its petrographic, reference collection. The use of that collection will be greatly facilitated by this work. Very respectfully. WHITMAN CROSS, G-I'O! fig !#t in Charye Section of Petrology. Hon. CHARLES I). WAL.COTT, Director IJ. S. G-eoloyhul PREFACE. The collection of chemical analyses of igneous rocks here presented was made during a period covering several years, for purposes of ready reference in certain lines of investigation. In view of the gieat value of that standard work of reference, Roth's Tabellen, and of the fact that no such collection of rock analyses has appeared since the last installment of these in 1884," it was thought that an extension and completion of these along the lines of Roth's work, so as to bring them down to the present day, would be welcome to petrographers. This seemed to be the more advisable because the years that have elapsed since 1883 have witnessed a very marked increase in the number, as well as a great improvement in the quality, of chemical analyses of rocks. These years have also shown a steady increase in the importance of chemical analyses as applied to the discussion of petrological problems, and a growing tendency to use them as bases for various systems of classification which have been proposed. The classificatory work on which I have been engaged in collaboration with Cross, Iddings, and Pirsson, the results of which have recently appeared,6 was also a powerful incentive to the formation of the present collection. As has been stated by us, this collection has been appealed to whenever possible, as a test of our proposed system of classification, and has also formed to a large extent the basis of the roots of the magmatic names suggested. The years embraced in the present collection are those from 1884, that of the publication of the last of Roth's Tabellen, to 1900, both inclusive. The former was selected as a starting point because Roth collected nearly all the analyses which appeared in 1883; yet some of those which he overlooked are included in this col­ lection. The year 1900 seemed to be appropriate as the other time limit, partly for the reason that it was the closing year of the last century, and partly because in that year appeared Bulletin 168 of the United States Geological Survey, which is the latest publication embracing all the analyses of rocks made by the chemists of that organi­ zation. At the same time, since the collection is to a large extent illustrative of our oRoth, J , Beitrage zur Petrographie der plutomschen Gestemo Sitzungsber K Preuss Akad Wiss, Berlin, 1884 ft Journal oi Geology, Vol X, 1902, p 555, also, Quantitative Classification of Igneous Rocks, Chicago, 1903 8 PREFACE. proposed S3'srem of classification and nomenclature, some analyses published prior to 1884 or subsequent to 1900 that are of especial interest or importance have been included, as illustrations of the classificatory divisions, or as forming the bases of the magmatic names. The endeavor