Preston not very seldom came and made himself agreeable; playing an occasional game of chess, and more often regaling Daisy with a history of his expeditions.  Other visitors Daisy had from Melbourne, now and then; but her best friend for real service, after her father and Juanita, was Dr. Sandford.  He took great care of his little patient’s comfort and happiness; which was a pretty thing in him, seeing that he was a young man, busy with a very good country practice, and furthermore busy with the demands made upon him as an admired pet of society.  For that was Dr. Sandford, and he knew it perfectly well.  Nevertheless his kind care of Daisy never abated.

It was of course partly his professional zeal and care that were called for; but it could not have been those that made him keep up his lectures to Daisy on the wonderful things she found for him, day by day.  In professional care those lectures certainly began; but Daisy was getting well now; had nothing more to trouble her, and shewed an invariably happy as well as wise little face.  Yet Dr. Sandford used to sit down and tell her of the things she asked about, with a sort of amused patience—­if it was no more; at any rate he was never impatient.  He talked to Daisy of the stars, which, with the moon, were very naturally the next subjects of investigation after the sun.

At last Daisy got him upon the subject of trilobites.  It was not difficult.  Dr. Sandford was far more easy to move than Preston—­in this matter at least.  He only smiled, and slid into the story very simply; the story that Daisy was so eager to hear.  And it did not seem less worth hearing than she had expected, nor less wonderful, nor less interesting.  Daisy thought about it a great deal, while Juanita listened and doubted; but Daisy did not doubt.  She believed the doctor told her true.  That the family to which her little fossil trilobite belonged—­the particular family—­for they were generally related, he said to the lobster and crab, were found in the very oldest and deepest down rocks in which any sort of remains of living things have been found; therefore it is likely they were among the earliest of earth’s inhabitants.  There were a great many of them, the doctor said, and many different species; for great numbers of them are found to this day in those-particular rocks.  The rocks must have been made at the time when the trilobites lived, and have somehow shut them in.  And the doctor thought it likely that at the time when they lived, there was no dry land in existence, but all covered by the sea.  He would not take it upon him to be positive; but this he could tell Daisy; there was never a stick or a leaf to be found in those old rocks that ever lived and grew on dry ground, though there were plenty that grew in the sea, until in the very topmost or latest of those rocks some few bits of fern growth began to appear.

“But what plants live under water?” said Daisy.

“Sea weeds.”