Northeastern Sonora Research Articles

An Arrangement of the Subspecies of the Horned Toad, Phrynosoma Orbiculare (Iguanidae)

The horned toads, Phrynosoma orbiculare, locally known as camaleones or tapayaxin are known to occur from northwestern Chihuahua and northeastern Sonora southward through the western mountains of Mexico to the southern end of the Mexican Plateau, and from the northern Sierra Madre Oriental of Nuevo Leon southward to Vera Cruz and the southern edge of the Central Plateau. The range may be stated as, the southern central plateau and adjacent eastern and western mountains. In this area the camaleon has become differentiated into five distinguishable subspecies. The Mexican horned toad, type of the genus, was first mentioned in print by Hernandez (1651), 107 years before the 10th edition of the Systema Naturae. Despite this long history, there are relatively few synonyms for the name orbiculare assigned by Lirnaeus. However, a brief historical review is essential to an understanding of the origin of some of the names used herein.

New Plants from Northeastern Sonora, Mexico and Notes on Extensions of Range

New Plants from Northeastern Sonora, Mexico and Notes on Extensions of Range

Cretaceous Formations of Central America and Mexico

Cretaceous Formations of Central America and Mexico

Paleogeographic Studies in Northeastern Sonora

Thick Upper Paleozoic offshore limestones and Cretaceous near-shore deposits in northeastern Sonora indicate the extent of the former seaways. Near El Tigre the Upper Paleozoic limestones attain a thickness of about 5500 feet, are like those in southeastern Arizona, and show the existence of a fairly broad persistent sea. Marked shoaling is indicated by the shaly character of the Upper Mississippian deposits. Near El Tigre the Paleozoic limestones are overlain by several thousand feet of near-shore deposits representing the Trinity division of the Cretaceous. Significant fossils include Parahoplites, Acanthoplites, Cheloniceras, Beudanticeras, and Exogyra aff. latissima var. aquila (Brongniart). Southward from the Bisbee district the Glance conglomerate and Morita formation increase markedly in coarseness and thickness, attaining over 8000 feet along the northern part of the Sierra de los Ajos. Similar coarse clastic deposits, extending from Cabullona to Santa Cruz, show deposition in a geosyncline adjacent to a rising and probably fairly high landmass which lay south of the Bisbee district and west of the El Tigre district. The transgressive character of the Trinity sediments on the Upper Paleozoic limestones suggests that the Jurassic and Lower Cretaceous seas older than Trinity time never extended as far west as Sonora. During the Laramide revolution the sedimentary rocks of the geosyncline were intensely folded, uplifted, and eroded to a surface of high relief which subsequently was buried by thousands of feet of Tertiary lavas. Extensive steep-angled faulting along north-northwest lines began in middle or late Tertiary time and at present controls most of the topographic features. . . .

Natural sodium compounds and borates in 1921

The prevailing theory for the formation of trona [Na3(CO3)(HCO3) · 2(H2O)] relies on evaporative concentration of Na+–HCO3- water produced by silicate hydrolysis of volcanic rock or volcaniclastic sediments. Given the abundance of closed drainage basins dominated by volcanics, it is puzzling that there are so few trona deposits and present-day lakes that would yield dominantly Na–CO3 minerals upon evaporation. Groundwater in the San Bernardino Basin (southeastern Arizona, USA and northeastern Sonora, Mexico) would yield mainly Na–CO3 minerals upon evaporation, but waters in the surrounding basins would not. Analysis of the chemical evolution of this groundwater shows that the critical difference from the surrounding basins is not lithology, but the injection of magmatic CO2. Many major deposits of trona and Na–CO3-type lakes appear to have had “excess” CO2 input, either from magmatic sources or from the decay of organic matter. It is proposed that, along with the presence of volcanics, addition of “excess” CO2 is an important pre-condition for the formation of trona deposits.

Allen's List of Birds Collected in Northeastern Sonora and Northwestern Chihuahua List of Mammals and Birds Collected in Northeastern Sonora and Northwestern Chihuahua, Mexico, on the Lumholtz Archæological Expedition, 1890-92 J. A. Allen

Allen's List of Birds Collected in Northeastern Sonora and Northwestern Chihuahua List of Mammals and Birds Collected in Northeastern Sonora and Northwestern Chihuahua, Mexico, on the Lumholtz Archæological Expedition, 1890-92 J. A. Allen