The Artesian Well--another View

Mr. Editor : la your yesterday's papcr I read an artlclc of Professor Wihciiki.l's, explalnlng the nature of the strata pcuetrated In the boring experiment ou Court House Square. Duriug the progresa of this wörk I have been a daily observer, aud lt inay therefore not appear immodeet lf I expresa, iu the game ; '.place, roy own opinión as far as lt diners from the Proiessor's views. He pronounces the thick rock bed which contalns the aalt brine a Dolomite, or to usc hls own ezpresslou, a magrunian rock, which rock was always by me represented as beIng a aandsloM, and which opinión I hold yct as flrm as ever. lt Is a moderately coarse gralned and rock, wlth nuraerous intereperscd leaflets of mica, and with a calcttreous cement, in consequence whereof it wlll effervesce wlth acids, but even after boiiing it witli a surplus oí aelds, only a small proportion oflt Is soluble, the preponderant portion remaius unaltered at the bottom without having lost rauch of its welght. Thls socalled Dofomüe is cousldcred by tho Professor as a representatlve. of the Haniilton Group, and he suggests lt even to be the equivalent of a certaln subordínate stratuiu in somc locallty of the north, but I fail to see any tangible reason to sustaln thls hypothesis, the of the rock contradicts it, and foEsils, which alone could bc decisivo In the question, have not been found yet. Also the presence of sult brlue, which lu Michigan usually occurs In the horizon of the so-called Marshall Group, In combinación with the chai'&cter of the rock, ouems to me more naturally explaiued by suggestlng the presence of this formatlon, than by SBsuminji an exceptloual state of thinus, without the slightest support for lts probablllty.