Among the nuggets you find if you dig this city, and one that's likely to keep its value, is a one-room exhibit at the Woodrow Wilson House (2340 S St. NW) next to the Textile Museum (both not nuggets but lodes). It is a retrospective on Hornblower & Marshall, the chaps who, even in their own time, were known as "the best Washington architects of the '90s," our very own McKim, Mead and White.

The firm was established in 1883. Twenty-five years later, Joseph C. Hornblower committed suicide on a trip to Holland; James Rush Marshall carried on for another 19 years. The two are important because they were the first Beaux Arts architects in this city. Hornblower, who was among the first Americans to apprentice at the famous Paris school, started to immerse Washington society (nouveaux riches merchants and Western senators) in ornate architectural luxury long before Daniel Burnham and his friends came here in 1910 to do the city over in the image of their Beaux Arts Chicago Columbian Exposition.

The firm is characterized by no specific characteristics; its buildings were simpler in form than others of the period. H&M could do anything - from Roman to Georgian Revival, including eclectic fruitcakes blended with taste and flair. They designed under the influence of Ornamental Infatuation, a kind of elexir that has since been declared harmful but is actually most pleasing to the eye.

Among H&M's unique houses are the yellow-and-ochre Boardman House, with its astonishing Syrian arch and whimsical second-story balcony, at 1801 P St. NW; the prettily sulking Edward Lind Morse House, with strange door hinges and door pull, at 2133 R St. NW; and the Duncan Clinch Phillips House at 2010 Massachusetts Ave. NW, now the Phillips Collection, that looks deceptively plain Georgian Revival, but on second galnce is a pleasing concoction of many styles. One of the few public buildings by H&M is the Smithsonian Museum of Natural History (which might have been more fun if the bureaucrats hadn't shaved the French dome design into bald Roman.

Many H&M houses are gone, foremost among them the Tuckerman mansion at 1600 I St. NW, a marvel of carved stone work that the Motion Picture Association demolished in 1967 for a massive office building.

What makes the Wilson House exhibit intriguing are the personal photographs, some by Frances B. Johnston, a friend of the architects and the first professional woman photographer in Washington; original drawings, interiors with fabulous mantels and original artifacts and ornaments from demolished buildings.

Walking through Washington's ritzler districts is never the same again. You keep looking for more Hornblower & Marshalls.