New Haven’s Sentinels: The Art and Science of East Rock and West Rock

Introduction

Introduction • 3 3. The Four Rocks of the New Haven Region. (Chester R.Longwell and Edward S.Dana,Plate II,1932.) This rather detailed map shows the outcrops of the four igneous complexes north of New Haven.West Rock and East Rock are thick,eastward-tilted slabs of basalt (sills) wedged between layers of sandstone.Pine Rock and Mill Rock are relatively thin sheets (dikes) that steeply intersect the sandstone formations.Sachems Ridge and Beaver Hills are glacial drumlins.The numbers represent elevations in feet. In 1852, author Mary Field described New Haven, Connecticut, this way: The Town is situated on a plain which opens northward into a beautiful valley, whose guarding hill-sides terminate in two rocky heights. When seen from the harbor below, these eminences seem near the city, and look like the sides of some huge portal thrown open in welcome to the traveler. They are known as East and West Rock. Together, East Rock and West Rock, along with Pine Rock and Mill Rock, form a fundamental part of New Haven’s skyline. To some, these craggy mounts resemble the ruins of a breached medieval wall; to others they mark monumental gateways. For centuries, this city of former rebels and abolitionists has nestled safely in the expanse between the Four Rocks and its shoreline. East Rock and West Rock are geotopes—geologic sites with noteworthy aesthetic, cultural, historic and scientific value. In the nineteenth century especially, they not only attracted the attention of geologists, but also of poets and painters. William Thompson Bacon, New Haven’s celebrated poet, wrote: What a proud scene is here! We stand upon these thunder-rive and ragged capitals winding round to the north like a blue zone. And, in his poem “East Rock,” Bacon expressed the wish that “the circuit of these hills—might shut me in forever.” 4 | New Haven’s Sentinels 4. Trap (basalt) areas of Central Connecticut. (James G.Percival,1848.) This map shows the distribution of basalt and diabase masses in the southern segment of the Connecticut rift valley between Hartford and New Haven. Introduction | 5 In the second half of the nineteenth century, more than a dozen artists sought to capture the magic of New Haven and its Rocks. Their paintings and prints heralded the advent of landscape scenes after more than a century in which portraitures dominated. Among these artists are renowned Frederick Edwin Church, born and raised in Hartford, and Hartford-born George Henry Durrie, famous for his farm and winter scenes. The combined output of this group of artists represents an imaginative body of work with considerable depth. It is classic American, uninfluenced by imported European styles. In his Statistical Account of the City of New Haven (1811), Timothy Dwight, president of Yale College, included a description by Benjamin Silliman, Yale’s acclaimed geologist, who described East Rock and West Rock as presenting: high mural precipices, perfectly naked and rude. Their fronts are composed of vast assemblages of columns, more or less regular, frequently affecting the prismatic form with considerable, and sometimes with surprising regularity . . . . Vast masses of broken rocks [scree], from the smallest size, to that of the largest columns, are usually found sloping from the bases of these mountains up their fronts [scarps], sometimes for more than half their height. They are also distinguished by sloping backs, declining so gradually, that, in the rear, ascent is often easy, while in the front it is impracticable. A few years later Silliman (1824) provided a more poetic description: [O]ne cannot contemplate these eminences without admiring them, as forming bold and beautiful features in the scenery around New Haven . . . . They are composed of precipitous cliffs of naked frowning rock, hoary with time, moss-grown and tarnished by a superficial decomposition, looking like an immense work of art. From the scientific viewpoint, East Rock and West Rock provide information on an important tectonic phase in Connecticut’s geologic evolution. Through their research, Silliman and his successors at Yale came to see the Rocks as the remains of igneous masses that date back to a scorching volcanic period in the Early Jurassic, when central Connecticut was covered with steaming lava flows. This volcanic event—about 201 million years ago—resulted from the tectonic breakup of Pangaea, which caused the separation of the North American and African continents and initiated the...