THE EXPLORERS By Richard F. Pourade CHAPTER ONE: BEFORE THE EXPLORERS San Diego was a well populated area before the first Spanish explorers arrived. The climate was wetter and perhaps warmer, and the land more wooded than now. The remnant of a great inland lake covered most of Imperial Valley. The San Diego River wandered back and forth over the broad delta it had formed between Point Loma and Old Town, alternately emptying into Mission Bay and San Diego Bay. The natural food supply was so abundant that the state as a whole supported an Indian population far greater than any equal area in the United States. The native population of the southern counties alone must have been at least 10,000. The early maps made of San Diego Bay by the Spanish explorers show the same general configuration as of today, except, of course, for the many changes in the shoreline made by dredging and filling in recent years. The maps, crudely drawn without proper surveys, vary considerably in detail. Thousands of years ago, in the late part of the Ice Age, Point Loma was an island, as were Coronado and North Island. Coronado used to be known as South Island. There was no bay, as we think of it now. A slightly curving coastline was protected by the three islands, of which, of course, Point Loma was by far the largest. What we now know as Crown Point in Mission Bay was a small peninsula projecting into the ocean. On the mainland, the San Diego and Linda Vista mesas were one continuous land mass. The San Diego River, in those days a roaring torrent, gradually cut a canyon five hundred feet deep through the mesa on its rush to the sea. The melting of the continental ice caps over thousands of years slowly raised the level of the ocean by a hundred feet, and, as it rose, the river lifted itself on the deposits of its own silt. The silt today is about one hundred feet deep in the bed of the river and forms the broad flood plain of Mission Valley. Through all these centuries the river poured its mud and debris into the open sea, building up a delta which eventually tied Point Loma fast to the mainland. All of the low flat land between Old Town and Point Loma is a delta deposit. This closed San Diego Bay on the north to make two bays out of one, Mission Bay on one side of the delta and San Diego Bay on the other. To the south another process was at work. Silt from the Tia Juana River did not produce a delta similar to that of the San Diego River. Instead, southwest storm winds or an eddy on the lee side of Point Loma shifted the river's sediments northward, depositing them in long sandy spits connecting North Island and Coronado to each other and to the mainland. Thus San Diego Bay was landlocked south and west. Mission Bay once was open to the sea and deep. But gradually material which was eroded from the south shore of La Jolla and cut from the embankment at Pacific Beach, along with sediments washed down from Soledad Mountain, was carried southward by waves and currents and deposited across the wide mouth of Mission Bay, creating the sandy spit of Mission Beach and leaving only a narrow tidal opening. And inside, a once usable deep-water bay was slowly choked up by deposits from the San Diego River. The expedition of Sebastian Vizcaino in 1602 first noted Mission Bay. Ensign Sebastian Melendes, sent out with an exploring party, reported it was yet a "good port." For many years it was known as False Bay. The shifting of the course of the San Diego River has been of considerable historical interest. Lieut. George Horatio Derby, of the United States Army Corps of Engineers, in a report to Congress in 1853 stated: "At the time of the first establishment of the Mission of San Diego, and the 'Presidio', or the military post, this plain, and in fact the whole valley for six miles above, was covered with a dense forest of sycamore, willow, and cottonwood, with an undergrowth of various kinds of shrubbery, among which the wild grape was most abundant. At this time, the river ran through the most northerly part of the plain, skirting the hills ... and emptied into False Bay. This course it continued until 1811, when, by continued deposit of sand, its bed was so much elevated that it altered its channel to the southwest, still however, emptying into False Bay, until 1825, when a great freshet occurring, it overflowed its banks, destroying many gardens and much property, and formed a new channel discharging into the harbor of San Diego. From the continued accumulation of sand, its course has somewhat fluctuated but has never been essentially altered since that period." In 1889, George Davidson, of the United States Coast and Geodetic Survey, set 1835 as the time when the San Diego River again began emptying into San Diego Bay. Old Spanish charts, made long before this time, also show the river emptying into San Diego Bay. Thus it shifted back and forth across its own delta. Lieut. Derby said that while Mission Bay once was sufficiently deep to admit vessels of considerable size, by 1810 it was filled with shoals and sand bars, and hardly deep enough at low tide for a sail boat. Lieut. Derby was sent to San Diego to restrain the river, to force it into a more permanent bed and prevent the threatened silting up of San Diego Harbor, as had happened with Mission or False Bay. The original Derby Dike was built of dirt in 1853-54, but had to be reconstructed in 1877. It ran from a point near the base of Presidio Hill to the inland foot of Point Loma, and successfully diverted the flow of the river back into Mission Bay, thereby saving San Diego Harbor. The report by Lieut. Derby of a heavily wooded river valley, and particularly the comments of the early explorers about a forest on Point Loma, troubled historians down through the years. They generally concluded that the explorers must have been mistaken, or their words not properly understood or translated. Fr. Antonio de la Ascension, who accompanied Sebastian Vizcaino, records in his detailed report of the expedition that on the morning following their arrival at San Diego in 1602: "The General ordered some men to go and look over a 'Montesillo' which protected the port from the northwest wind. Captains Alarcon and Peguero and Father Antonio went with eight harquebusiers and found on it many live oaks, junipers, and other trees such as rockrose, heather, and one very similar to the rosemary. There were many fragrant medicinal and healthful herbs. From the top of the hill all that spacious ensenada (bay) could be clearly seen. It was a port very capacious, good, large and safe, as it was protected from all winds. This hill is about three leagues long and half a league wide, and to the northwest of it there is another good port." Historian Henry R. Wagner wrote that strictly speaking the word "monte" means a forest or thicket but he concluded that, as there is no likelihood that Point Loma was covered by trees other than some scrub oak and brush, Fr. Ascension undoubtedly used the word in its other variation of "little mountain." Richard Henry Dana, the author of "Two Years Before the Mast," who visited San Diego in 1835, wrote of a "large and well-wooded headland," but also commented later that wood was very scarce in the vicinity of San Diego and that the trees were small ones growing in thickets. But perhaps they weren't so mistaken. There is considerable scientific evidence that the area was much wetter at one time and that the last three hundred years have been relatively dry. Dr. Carl L. Hubbs, of the Scripps Institution of Oceanography, in climatic studies has shown that large populations of Indians lived in places where now they could not possibly find enough fresh water to live. He has also shown that a fresh-water lake, one hundred and five miles long, thirty miles broad, and three or four hundred feet deep, once filled the Salton Sea Basin. It is known as Lake LeConte, Lake Cahuilla, or Blake Sea. As the weather turned drier and the Colorado River swung to the east so as to discharge directly into the Gulf of California rather than through the Salton Sink, the great lake rapidly disappeared, evaporating probably at the rate of about five feet a year, though it was still in existence until about three hundred years ago. Recession lines left as the lake dropped were visible until the last few years, during which jeeps have messed up the evidence. The memories of this great inland sea lived in Indian legends, and Spanish explorers were sufficiently impressed to place it on maps. Spanish explorers also reported forests of trees at Santa Barbara, to a greater extent than now, and their maps show the lower part of the Central Valleys of California covered with swamps and marshes. Much of this growth and wetness, if they did exist, have largely disappeared with declining rainfall. Dr. Hubbs believes the desert, in the Southwest in particular, has been getting drier over long periods of geological time, and that the prospect is for continued aridity, broken by occasional wetter periods, and thus for a continued march of the desert.